May 27, 1997 — The Jarrell, Texas Tornado

 [Click photos to view larger versions.]

Nestled in the Blackland Prairies at the edge of Central Texas’ Hill Country lies the small community of Jarrell. It’s a land of contrasts, with a small-but-developing town center carved into the low, rolling hills and patchy farmland. Clumps of Indian paintbrush and Texas bluebonnet provide blotches of color against the muted greens and browns of shortgrass and crop fields. A sharp, black, six-lane ribbon of asphalt bisects the town, carrying drivers between the metropolitan areas of Dallas, Waco and Austin.

If the town of Jarrell is divided by that flat, sun-baked stretch of Interstate 35, so too are its people. To the east of the interstate, the march of progress has taken hold full-force. A brand new water tower glints in the midday sun, rising more than 200 feet above its surroundings. Newly elected mayor Dewey Hulme talks excitedly about his plans for a reinvigorated Jarrell, one in which the new water tower and a sprawling 46-acre town center — planned out on a vast 153-acre parcel of land near the interstate — will begin to attract the kind of commercial and residential growth that could transform the town.

To the west of I-35, there is no water tower. There are no freshly built developments and new businesses. There is no talk of transformation. Instead, there is the stark land surrounding County Road 305. There is a park with a small community center, flanked by two emerald-green baseball fields. There is a simple memorial plaque, white lettering etched into sepia-toned granite, and a semicircular entrance ringed by trees – 27 of them. Most of all, there is the ever-present memory of the day nature conspired to wipe 50 homes and 27 of Jarrell’s mothers, fathers, children, friends and neighbors from the face of the Earth.

Jarrell Memorial Park

The Jarrell Memorial Park, with several of the 27 trees planted to honor tornado victims.

The morning of May 27, 1997, dawned much the same as any other Tuesday during late spring. In Jarrell, the mercury rose to 79 degrees before the sun had even begun to break the horizon and filter through the scattered stands of hackberry, cypress and juniper. The air hung heavily, nearly opaque from the stifling humidity. The wind offered little relief, as a light southerly breeze only served to bring in more sticky air. By midday, dew points across the area skyrocketed to nearly 80 degrees. With temperatures approaching 90 degrees, even lifelong residents complained about the brutal conditions.

At the Storm Prediction Center (SPC) in Norman, Oklahoma, forecasters closely monitored the atmospheric conditions. A low-pressure system had progressed eastward toward southern Missouri overnight, leaving a trailing cold front draped across North Texas. Hot, dry air from the high elevations of the desert Southwest pushed eastward, sliding uneasily atop the warm, muggy surface air of the Southern Plains and trapping it beneath it. Where this dry layer of air tilted and sloped down to the surface — on an arching line roughly from Dallas to Del Rio — a dryline formed. A weak secondary low had developed just north of Dallas and begun to propagate southward along the dryline, helping to pull in more moist air from the southeast.

6z Hand Analysis

Hand analysis of the 6z  (1 am CDT) surface map reveals a cold front over central Oklahoma and northern Texas, a dryline across central Texas and dying convection across northern Mississippi and Alabama. The secondary low is evident on the dryline in north-central Texas, northwest of Dallas.

The layer of dry air at the mid-levels acted as a capping inversion, inhibiting vertical motion and suppressing thunderstorm development. For several days, a persistent onshore flow allowed a vast, moisture-laden airmass to overspread the Texas countryside. With no way to disperse its energy through convection, a massive influx of radiation from the late-spring sun had left the tropical airmass seething and boiling. Forecasters measure this trapped energy in terms of CAPE, or Convective Available Potential Energy. A CAPE of 500 j/kg is adequate to ignite thunderstorms, while values of 2,000 j/kg or more indicate extreme instability. Early in the afternoon, conditions over much of eastern and central Texas produced CAPE values of more than 5,500 j/kg. At Temple, 25 miles northeast of Jarrell, surface observations indicated an incredible 6,840 j/kg.

18z Temple Sounding

Special 18z (1pm CDT) sounding created at Temple, Texas. The broad red-shaded section illustrates the extraordinary CAPE present in the atmosphere.

It was clear that severe thunderstorms were likely given such an unstable atmosphere, but the forecast was a difficult one. As is typical in the deep south during late spring, winds aloft were generally light. This lack of wind shear suggested that supercells and tornadoes were probably unlikely. In the presence of light wind shear, a thunderstorm updraft is not sufficiently separated from its downdraft, leading to quick bursts of convection that blow up and then quickly choke themselves with rain. The forecast was complicated, however, by the presence of the cold front and dry line. If storms could develop along these boundaries, the locally enhanced wind shear could be enough to allow tornadic supercells. Acting more out of caution than expectation, the SPC issued its first tornado watch shortly before 1 pm.

1254 PM CDT TUE MAY 27 1997










In Jarrell, life continued unimpeded. Jarrell’s local high school had just dismissed for the summer, and many children were eager to begin their vacations. Brothers John and Michael Ruiz, 15 and 14 respectively, hurriedly ate their breakfasts and rushed off to the local high school to shoot hoops in the gym. Twins John and Paul Igo, aged 15, joined their father Larry on his way to the antique auto parts store that he owned and operated near the center of town. Seventeen-year-old Audrey joined her mother, Joan, at the local school, where she taught special needs children.

The Igo Family

The Igo family. From left to right: John, 15; Joan, 45; Paul, 15; Larry, 46; and Audrey, 17.

The Igos were among the most well-known and well-liked families in Jarrell. Larry Igo served as music director for Jarrell’s Baptist Church, where the entire family sang in the choir. Brothers John and Paul were active on all the local sports teams, and the family was always at the head of community projects. Audrey had a particular talent for music, often performing beautiful recitals, singing and playing multiple instruments for the community. To the delight of the community, she’d recently made plans to attend the University of North Texas to pursue music after her final year of high school.

Hundreds of miles to the east, thunderstorms which had formed along the dryline in Oklahoma the previous evening had begun decaying over northern Mississippi and Alabama. As the storm complex sputtered and dissipated, the atmosphere around it began to ripple like the surface of a pond. These ripples, known as gravity waves, rapidly spread over much of the southeast and propagate toward the Southern Plains. At the same time, the cold front over North Texas continued its slow progression to the southeast. With the dryline stalled over central Texas, the cold front began to overtake it.

16z Hand Analysis

16z (11 am CDT) hand analysis shows the cold front approaching and beginning to overtake the dry line across central and western Texas. Incoming gravity waves are shown as a wavy, northwest to southeast line over east-central Texas.

By noon, the first large towers of cumulus cloud burst into the sky near the dryline just north of Temple. The timing could not have been worse. As the sun rose to its zenith and daytime heating neared its peak, the cold front had finally overrun the dryline, allowing convection to begin chipping away at the cap. Within half an hour, the gravity wave – just arriving in central Texas and oriented perpendicular to the dryline and cold front – began to expand and compress the atmosphere around the fledgling storm system. Fueled by the procession of rising and sinking air, the growing tower ruptured the cap, allowing the extraordinarily unstable air below to begin rocketing toward the tropopause.

As the thunderstorm’s updraft developed, its rapid acceleration helped to pull in vast quantities of hot, muggy air near the surface. The air raced in toward the center of the storm before being violently propelled upward, creating such a contrast in speed and direction with the air above that the storm began to produce its own wind shear. The resulting local shear, or storm-relative helicity, generated rotation parallel to the ground called horizontal vorticity. This rotation was soon ingested into the storm itself, where the vigorous updraft tilted it vertically and began to spin. A supercell was born.

Visible Satellite

Visible satellite. Click to animate. Annotated first frame shows the cold front (blue line), dryline (yellow line) and propagating gravity waves (orange lines). Note the explosive supercell development shortly after the lead gravity wave intersects the dryline.

Still under the influence of the passing gravity wave, the supercell began to drift unexpectedly southwestward. Soon it produced its first tornado near the town of Lorena, where several mobile homes and a frame house were damaged. Tornadoes of varying intensity also struck Moody, Belton and Temple. The worst, however, was yet to come. Rather than becoming outflow-dominant as most storms do on low-shear days, the massive supercell sustained itself by propagating southwest along the cold front/dryline and constantly regenerating its updraft with extremely unstable air. Finally, at 3:30 pm CDT, a tornado warning was issued for Williamson County in south-central Texas.

330 PM CDT TUE MAY 27 1997







Within minutes, the frightful wail of tornado sirens reverberated through the town of Jarrell. Residents stole nervous glances at the suddenly menacing sky. The Ruiz brothers quickly grabbed their basketball and headed home. Larry Igo rushed to close his auto parts store, ushering twins John and Paul to the car. At the same time, Joan and her daughter Audrey packed up and left the school in a rush. Familiar words of warning echoed from televisions and radios throughout the county, the same safety precautions that folks in the Midwest knew by heart: seek shelter in the innermost room on the lowest level of a sturdy, well-built structure. Protect yourself as best you can. Hang on. Pray.

Just off I-35 on Double Creek Drive, the trumpeting sirens preceded a flurry of activity. John and Michael Ruiz arrived home, but they knew their small trailer offered little protection. As they’d always been told to do, they left to seek shelter in the well-built, two-story home of the neighboring Moehring family. In their front yard, Keith and Cindy Moehring stood with their sons, Erik, 16, and Ryan, 15. Together the neighbors stared with rapt attention as the northern sky filled with writhing, twisting masses of sooty cloud. The brilliant afternoon sunshine quickly faded, tinged an unearthly greenish-gray by the incoming storm.

Overpass along I-35

Cars parked along I-35. Note the people sheltering underneath the overpass to the right.

Just to the east, traffic along the interstate had come to a standstill. From a lowering at the edge of the cloud deck, a slender rope of condensation began slithering earthward. Thin wisps of dirt and water vapor emanated from the ground, circling and gyrating about a common center like an ethereal dance. Some motorists pulled to the shoulder to gawk at the developing tornado. Others abandoned their vehicles to take shelter in the perceived safety of a highway overpass. Within minutes of forming, the fiercely spinning funnel began to undergo vortex breakdown. A complex interplay of updrafts and downdrafts within the tornado worked to split the singular column into a series of threadlike suction vortices.

The supercell’s slow movement afforded many in Double Creek Estates an uneasy, transfixing view. As residents looked on, the funnel again began to change. Ragged strands of cloud and vapor rushed to join the maelstrom, tearing soil from the earth. The entire inky sky appeared to reach downward, grasping fervently at the ground below. The funnel pulsed and breathed, growing ever-larger as it meandered south-southwest. Nearby oak trees began to sway, gently at first, then bent and jerked under the tremendous force of the wind. Large branches gave way first, followed by entire trees and full canopies, snapping off like oversized florets.

On Double Creek Drive, the dull drone in the distance began to grow deeper, louder, more ominous. From an indistinct smudge dotting the northern horizon, the storm had grown to devour the sky. Rain fell fitfully, rising from a light drizzle to a torrent, turning the remaining sunlight into a diffuse haze. Those who had not yet sought shelter frantically searched for protection. The Moehring family huddled at the center of the house, joined by the Ruiz brothers, still praying that this warning, like so many others, would be a false alarm. Larry and Joan Igo arrived home within moments of one another. Urging their children inside, they too sought shelter from the howling storm.

Billy and Debby La France had instinctively sprinted to the bathroom at the first blast of the siren, knowing the bathtub offered the only bit of protection they could find. Billy placed his ten-year-old daughter Kristin in the tub. Exchanging the sort of knowing glance that comes with more than two decades of marriage, Billy knelt on the floor as his wife joined Kristin in the tub, doing her best to protect their daughter as the roar closed in around them. Rain lashed the windows. Hail spattered and thumped upon the roof. Wind seemed to infiltrate every crack and crevice, hissing and whistling like an angry tea kettle.

Electrical wires embedded into tree

Interior electrical wires deeply embedded into a completely debarked tree by the extreme winds.

Tatters of murky cloud raced by overhead, falling inexorably toward the vacuum of the storm’s low pressure. The sky shimmered with broken remnants of domestic life: ragged splinters of timbers, aluminum flashing, batts of insulation. The tornado, an anemic cloud of dust and dirt just minutes before, had exploded in intensity as it lurched toward the west side of Jarrell. Winds inside the chaotic tangle of vortices likely exceeded 200 miles per hour, perhaps significantly higher. The funnel continued to grow, devouring anything and everything in a swath at least three-quarters of a mile wide.

As the tornado approached the intersection of County Roads 305 and 307, it reduced a recycling plant and several trailers and other structures to rubble. Thick steel beams at the plant were bent and contorted. Trees and utility poles were twisted and snapped just above ground level. Vehicles were tossed and rolled hundreds of yards, deposited across the surrounding countryside in completely unrecognizable lumps. More than 500 yards of asphalt — the length of five football fields — was torn from CR305 and promptly disintegrated by the furious winds, leaving the roadbed scoured out. Fields, too, were scoured down to the bare earth. In some areas, as much as 18 to 20 inches of grass and topsoil were stripped from the ground.

Recycling Plant

A couple looks in disbelief at the remains of the local recycling plant. Photo via Matthew Crawley.


Extensive asphalt scouring along County Road 305.

Extensive asphalt scouring along County Road 305. The utility poles were erected after the storm.

Continuing along County Road 305, the tornado began its deadly rampage in earnest. The Igo home was among the first to be impacted. Large chunks of debris shattered windows and pounded exterior walls. The roof began to peel off and lift like an airplane wing, aided by the aerodynamic uplift of the intense winds. The exterior walls, no longer supported by the roof structure, collapsed almost instantly. Anchor bolts in the foundation were sheared cleanly away. The interior walls followed quickly behind, demolished and swept away by the immense force. Within seconds, all that remained of the Igo family home was a foundation strewn with small bits of rubble. The tornado had claimed its first five lives.

Video of the tornado growing from a thin rope to a massive wedge as it barrels along CR-305.

Nearing peak intensity, the tornado ground its way into Double Creek Estates. A horizontal vortex tube, fairly common in extremely intense tornadoes, can be seen near the bottom.

Nearing peak intensity, the tornado ground its way into Double Creek Estates. A horizontal vortex tube, fairly common in extremely intense tornadoes, can be seen near the bottom.

The Igo home was swept cleanly away, leaving nothing but a bare foundation.

The Igo home was swept cleanly away, leaving nothing but a bare foundation.

Moments later, the tornado barreled into the Double Creek Estates subdivision. The Moehring family and the Ruiz brothers clung together as the tornado bore down, issuing frantic prayers into the deafening tumult. The wind came first in spasms; brief, intense gusts stripped shingles, smashed windows and pelted walls with rocks and other small debris. The cacophony grew as the tornado inched closer, peeling roof decking off like the lid of a tin can. Because of the agonizingly slow forward speed of the tornado, most structures were exposed to the tempestuous winds for several minutes. Even well-built homes such as that of the Moehrings, with evenly spaced anchor bolts and sill plates that met or exceeded the local building code, were no match for the sheer duration of wind force.

Despite being well-anchored to its foundation, the Moehring home was no match for the violent wind.

Despite being well-anchored to its foundation, the Moehring home was no match for the violent wind.

Shortly after, the La France home began to rip apart. Debby La France clawed desperately at the porcelain tub beneath her, resolved to give her life to protect her child. She maintained consciousness long enough to witness her roof hurtling skyward into the storm, followed shortly by her husband. Exposed to the full fury of the wind, the entire house began to disintegrate. Debby and her ten-year-old daughter were ripped from their tub and became airborne. The same scene repeated all across Double Creek — homes ripped from their foundations, vehicles shredded, the remnants of daily life pulverized and added to the devastating, churning, debris-clogged vortex.

Engine Block

A badly damaged engine block embedded into the ground outside of Jarrell. The car to which it belonged was never found.

Seven and a half miles and 45 minutes after it began, the Jarrell tornado dissipated near a treeline southwest of the town. Left in its wake was the most complete devastation ever wrought by a tornado. Where an entire community had been just minutes earlier, virtually nothing remained standing. Each of the 38 homes and three businesses in the tornado’s direct path was reduced to a bare foundation, the resulting debris so finely granulated that it was difficult for surveyors to see from the air. Vehicles and farm equipment were thrown great distances and left in mangled, unrecognizable heaps. Some vehicles disappeared entirely, unable to be located even after detailed damage surveys. Most trees were stripped completely of bark and branches, leaving only gnarled stubs. Virtually every blade of grass and clump of vegetation within the tornado’s three-quarter mile wide swath was scoured away, leaving nothing but mud.

In Double Creek Estates, twenty-seven people were killed. The entire Igo family was gone. The school and the auto parts store they‘d fatefully decided to leave were left virtually untouched. The Moehring family, too, perished in the terrible storm. The Ruiz brothers, despite making the right decision in seeking more sturdy shelter, were also lost. Their trailer stood a short distance away, undamaged. Their mother Maria was killed as well, engulfed by the tornado as she drove home to be with her sons. The list of fatalities also included 41-year-old Billy La France. In total, six separate families lost at least two members to the tornado.

Homes Swept Away

Virtually every home in Double Creek Estates was swept cleanly away, with very little debris left behind.

Two people were killed when this home was swept away. Another bare foundation can be seen on the left side of the photo.

Two people were killed when this home was swept away. Another bare foundation can be seen on the left side of the photo.

The Search for Victims

Dozens of volunteers combed the fields near Double Creek Estates in search of survivors and, more often, remains.

After the storm had passed, emergency officials and concerned citizens began to trickle into the devastated area to assist in search and rescue. Linking arms to form a long human chain, they waded through the muddy, swampy, debris-strewn fields in search of survivors. Many would later report the tornado was so violent that they had difficulty distinguishing between human and animal remains. It would take many days before the final death toll could be arrived at, and much longer before each victim could be positively identified. However, amid the overwhelming destruction was one ray of hope.

As search and rescue volunteers canvassed the area, they approached the lot on which the La France home had formerly been. In a nearby field, partially buried and caked with mud, rescuers stumbled upon ten-year-old Kristin La France. She was badly hurt and covered nearly head to toe in blood, but alive. A short distance away, Debby La France was found clinging to the remains of the peach tree in her yard. Despite her severe injuries, she too would survive. If it had not been for the fortuitous placement of her favorite tree, she almost certainly could not have survived.

Today, there are few visible scars left from the Jarrell tornado. Double Creek Estates has been largely rebuilt, though two lots still remain blank. The trees have returned. The grass, ripped from the ground by the winds, has grown back. County Road 305 and Double Creek Drive have since been repaved several times. Many businesses, too, have rebuilt and returned to normalcy. The memorial park, along with its twenty-seven trees and two baseball fields, was built on land donated by relatives of the Igo family. The same land on which Larry, Joan, John, Paul and Audrey had lived and died together.

The emotional scars, too, have largely faded with time. In the years following the tornado, both adults and children became frightened at the first rumble of thunder or gust of wind. The community grieved for the loss of Audrey’s beautiful singing, of Joan’s inspiring leadership, of Larry’s presence in the community and his passion for classic cars. The school, its teachers and its children mourned the loss of brothers John and Michael Ruiz, twins Paul and John Igo, Audrey Igo and all fourteen of the children whose lives were unfairly taken too soon. Some of those who remained moved away to escape the pain they would forever associate with Jarrell. Others simply couldn’t afford to pick up the pieces and rebuild.

Today, most children have only the vaguest sense of what happened on that May afternoon a decade and a half ago. Most of the adults, too, have little or no direct connection with the tornado. Of those who do, the wounds have healed as much as could be expected. Indeed, in the “new” Jarrell, east of Interstate 35, there is a relentless drive to minimize the past, to escape the tragic, painful legacy that so few residents are now bonded to, and to plunge headlong into a future that could be bright indeed for the little town. But west of the interstate, May 27, 1997, still holds a tangible presence. The colorful blotches of Indian paintbrush and Texas bluebonnet are now joined by smooth, glimmering white structures dotted across the land like ant hills: storm shelters.


Below is a gallery of additional photographs which couldn’t be fit into the article.

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77 comments on “May 27, 1997 — The Jarrell, Texas Tornado

  1. Was there a documentary that aired on TLC a while back that featured video of the vortex breakdown, the transition from rope to wedge, and the so-called “Dead Man Walking” where the suction vortices were clearly visible? If so, is it available anywhere?

    • I do recall a documentary similar to what you mentioned and I’m pretty sure it aired on TLC, but although it showed the multivortex structure I don’t think there’s actually any video of the “Dead Man Walking.” I haven’t been able to find that documentary online.

      I contacted someone who said they thought they had it on VHS and could convert it, but I haven’t gotten any updates on it lately. Maybe I’ll check in again and see what’s up. There’s some good video in the HBO special “Fatal Twisters: A Season of Fury” as well.

    • I don’t know of any video but the original Time magazine article on the Jarrell tornado has a photo of it. It was taken by Scott Beckwith. I still have the original magazine article.

    • I can remember that day. My family and I were coming back from Wichita Falls Texas, as we were getting closer to Hillsbro Texas we weren’t able to receive anything over the radio, And as we were driving closer to Lorena Texas I spotted a huge cloud, and I jokingly told my husband we brought back some tornadoes with us. We were right behind the Huge massive cloud. When were finally got to Temple Texas we were able to get a station on the radio. It was then that we learned about the Tornado that hit Jarrell Texas. We live in San Marcos Texas.

    • Well for the most part this story is true, with one exception! The Moehrings house was only one story! Actually Keith, Erik and Ryan, were at home! My sister Cindy was in another part of Jarrell cleaning a house. Arter realizing the tornado was heading towards there home, she left immediately to return to her husband and her boys! Unfortunately the whole family was killed, along with the two Ruiz boys. The house my sister left was untouched by the tornado!

    • While these are not documentaries per se, I have uncovered and uploaded two different videos of the tornado within the last year. Both contain great vantage points of the storm early on, and one contains the complete transitioning phase believed to be seen as a part of the documentary posted in this reply thread.

      Tornado’s first few minutes of life and wedge stage (no transition):

      This contains the complete transitioning phase:

    • Sure it is. I don’t have any soundings showing 10,000+ j/kg, but I’m sure it’s happened in Bangladesh. Just before the monsoon season (especially in late April and May) CAPE values can sometimes reach 5,000 j/kg, and there have been at least a couple instances of 9,000 j/kg or more. There’s such a tremendous influx of heat and moisture that it isn’t uncommon to see temperatures of 35°C (90-95°F) with dew points of 26°C (80°F) or higher.

      As for the United States, I recall a few instances where CAPE values hit 8,000+ j/kg, but I can’t recall any examples of 10,000. It certainly could have happened, and I’m sure at some point in history it has, but no specifics come to mind.

    • There was a discussion on Stormtrack in which one member mentioned that he saw such a documentary as well. I’ve heard a few people say that, but I always thought the photo was all that existed of the “dead man walking.” There’s some excellent footage of the tornado out there, but I’ve never seen anything like that. If you do happen to find it, though, I’d love to see it!

  2. I don’t understand how such a powerful tornado can happen so far south. What’s the “gravity wave” deal? How did it sustain itself?

    I live in Houston 5 counties away we don’t have basements 😦

    • It isn’t the most common place for tornadoes to occur, but it’s definitely not unprecedented to have them that far south. In fact there have been a number of tornadoes across the border in Mexico, especially in the Serranías del Burro region, some of which appeared on radar to be very intense (almost no structures in that region, so no damage surveys were possible). Houston is reasonably safe as far as tornadoes go, though there have been a couple of strong/violent tornadoes (Nov. 1992, for example).

      How did the gravity wave sustain itself, or do you mean the supercell/tornado? It helps to imagine gravity waves in the same way as waves in water. Let’s say you throw a rock into a pond. The rock acts to force the water downward, which creates a pressure perturbation that forces the water back upward in the form of a wave that’s higher than the surface of the surrounding water. At that point, gravity acts to pull the water back down. This, again, causes a pressure force that pushes the water back upward again. This cycle continues in a decaying fashion until eventually everything evens out.

      A similar thing happens with gravity waves, except that in this case it’s a cold pool from a strong line of thunderstorms that acts as the initial rock thrown into the pond. The waves propagate for hundreds of miles, and when they cross paths with a supercell they can interact in various ways. It’s a bit complicated and the mechanisms aren’t really well understood, but basically there are two ways gravity waves can give storms a boost. The expanding and compressing motion can help to rupture the cap in places that may otherwise not have ruptured, allowing for storms to develop. For storms that are already developed, gravity waves can cause locally increased helicity/vorticity (essentially, boosting the amount of spin in the storm) which is thought to help produce tornadoes.

  3. I vaguely remember that day but as usual the local news was too busy being dramatic instead of breaking down how actually powerful it was. Oddly people forgot about it quickly. I didn’t know it was that powerful at the time. People still try to downplay how powerful it was because of it’s slow movement

    • Yeah, the ‘slow movement’ argument is due in part to a study done by some engineers that found the majority of the damage could have been caused by winds in the F3 range. I’m sure that’s the case for some of the damage, but in my mind there’s little doubt about the intensity of this tornado. There have been several slow-moving tornadoes, but none of them have caused the sort of complete destruction Jarrell did. Deep, widespread ground/pavement scouring, extreme granulation of debris, vehicles, farm equipment and people thrown great distances and absolutely mangled, etc. I’ve never seen anything quite like the aftermath at Double Creek Estates in any other tornado.

      • I know the Harper, Kansas tornado on May 12, 2004 was rated a high-end F4 because it was stationary over the residence for five minutes. Damage is very similar to Jarrell but over a much small area.

  4. thnx shawn that was awesome you really know your s*& @ lol. (i think you’re on youtube also i remember you avatar). are you on extreme planet also?

    • Haha, thanks Luka. I’ll talk tornadoes pretty much anywhere and sometimes I end up spending more time in Youtube comments than the videos themselves. I can’t help it lol. And yeah, I read Max’s Extreme Planet blog as well. He’s a good guy and he really knows his stuff.

      • This Jarrell tornado is strong as hell, nothing i never before, I don’t think a skyscrpe can with stand this one.

  5. I lived in Dallas at the time and drove to Jarrell 3 days later to help. I walked for hours among the rubble looking for photos and anything else that was salvageable. I turned photos over to home owners and turned in the rest to an aid station. One woman who stood in what was left of her home told me that 5 minutes after the tornado hit there was a looter in their house. I stood on the bare cement which was once a home. It was wiped clean. I’ll never forget what I saw and the looks on people’s faces.

  6. What are the highest estimated winds speeds that a tornado has reached based on damage done or debris motion? Generally speaking, after winds get above 300 mph, basically even the strongest of buildings cannot withstand that correct?

    • It’s hard to estimate high-end wind speeds based on damage, so most EF5 tornadoes are just assigned the generic 205-210 mph. The problem, as you mentioned, is that once you get above the EF5 threshold (200+ mph) there really isn’t anything left of a well-built frame home. There are buildings that can withstand wind speeds higher than that, but they very rarely get hit by tornadoes.

      There is a technique called photogrammetry, which involves a complicated process of analyzing the motion of debris in a tornado to estimate wind speed. The highest photogrammetry-derived estimate I’m aware of is 284 mph for the tornado that struck Parker City, Indiana during the 1974 Super Outbreak, though I think Tom Grazulis estimated the wind speed in the 1995 Pampa, Texas tornado may have been above 300 mph. Other than that the only way we can get reasonably accurate wind speeds is via doppler radar.

  7. fascinating! What kinds of structures are capable of holding up to such strong windspeeds? Can’t they damage even steel reinforced concrete structures?

    • The first type of structure that comes to mind is dome-shaped homes. On May 24, 2011 there were two dome homes that survived direct hits from an EF4 (likely EF5, but didn’t hit well-built structures) tornado near Blanchard, OK, and they both survived and no one was injured:

      They’re constructed with a thin shell of concrete covering a very hard steel-reinforced fiber structure, and their shape and construction make them very resistant to wind damage.

      Other structures that may be able to withstand higher winds are institutional buildings (hospitals, jails, universities, etc) and steel-framed high rises. If they’re especially well-built they may be able to withstand winds as high as 270-290 mph according to the upper-bound estimates for the EF scale. Higher than that and you may get extreme structural deformation, if not total destruction.

      I wish we had more reliable ways to estimate wind speeds, but unfortunately we still don’t know a lot about it. Most of what we know about wind speed and tornado structure and so on comes from mobile radars, and it’s pretty difficult to get the trucks positioned to be able to observe tornadoes as they happen.

      • What type of tornado winds you think it take to suck those builders ( steel-framed high rises, Skyscri, hospitals, jails, universities ) off there foundation?

        I also wonder how strong a tornado have to be to take those builders off there foundation?

  8. I’m also just curious to know but do you think that incredible powerful rare tornadoes such as the Jarrell tornado might even be able to severely damage monolithic domes with its combo of high winds and slow movement?

    • Thanks for the compliment! Yes, although FEMA states that monolithic dome homes offer “nearly absolute protection” from even EF5 tornadoes, I think it’s possible in some cases a particularly violent tornado could destroy one. The most likely scenario would be a structural defect of some sort, but a sufficiently heavy object thrown by a tornado could possibly cause enough damage even to a well-built one that the wind would then be able to enter and cause total failure of the structure.

      It’s not all that uncommon for violent tornadoes to throw objects weighing several tons, and an impact from an object like that would impart a heck of a lot of force. The Tuscaloosa tornado, for example, picked up a railroad car weighing something like 35 tons and threw it nearly 400 feet upstream. Those domes are extremely strong, but I’m not so sure they’re quite that strong.

      As far as wind alone, I don’t think even the most violent of tornadoes could destroy a monolithic dome.

      • It worth noting that even a wooden building that is properly anchored can withstand a lot of wind. Take the example of the building on Mt. Washington that withstood 231 mph and not just for 3 seconds. It was chained down and the wind pressure didn’t cause any problems. If there had been debris then that would have been a different story. It withstood ef4 to ef5 winds for hours. See the following link.

        The NIST report for the Joplin tornado cites a wooden apartment building that was near St. Johns and received relatively minor damage and no one was killed in it. It was built properly with tie downs and a complete load path from roof to ground.

        In a lot of cases the buildings fail where walls are joined or the roof is attached.

        In a house the roof is usually blown off when the building loses envelope integrity and winds blasting into the structure blow it up like a balloon. That’s why it’s so important to have a continuous load path from ground to the roof so that you don’t lose your roof.

        I agree with Shawn, those domes may be really tough but you never know what is coming in the form of debris. If I had one of those dome houses, I’d still want either a basement or a safe room just in case.

        I wonder what they use for windows and doors? Windows and doors are weak points. I imagine that there must be shutter to protect the windows. Not sure what they do to protect the doors. Anyone know?

      • Yeah, high-quality construction can make all the difference. Any slight weakness in the load path will be torn apart by a tornado, and sometimes something as simple as hurricane clips can be the difference between minor damage and significant destruction. You can often pick out homes that are more well-built from aerial photos because they’ll be the only ones left standing. Of course, that can also be caused by multiple vortices leaving complicated damage patterns.

        It’s also worth noting, though, that the winds atop Mt. Washington, while extreme, aren’t really comparable to tornadic winds. It’s not just the incredible velocity of a tornado, but also the extremely chaotic mix of updrafts, extremely rapid wind shifts and violent accelerations. And, of course, the debris is ultimately what causes the most devastation.

        To answer your question about the monolithic domes, they use a range of materials depending on what the customer wants. For people who build domes for tornado-resistant purposes, they normally use 3″ thick Vistabrik for the windows, which is basically laminated ballistic glass. The doors are pretty much the same as those used in storm shelters, which is 1/4″ plate steel with a steel tube frame. Although, for some reason, some people (see the dome from Blanchard, OK I linked above) opt for more traditional windows and doors that offer very little protection.

  9. First, fantastic and informative site, well done!
    The lack of further study of this tornado is perplexing to me to say the least. The “slow moving” theory seems to be ignorant of the facts and physics and damage evidence of what happened during the time the tornado was at its most intense. As a person who has a bit of an addictive habit of consuming mass amounts of information on tornadoes, I consider myself to be well informed on the history and assessments of many famous/infamous f4/f5 events. The Jarrell tornado in my opinion was the most violent tornado in history when factoring in the death toll, ground scouring and damage in the Double Creek Estates subdivision. I’ve yet to see anything comparable and if there is, please bring it to my attention.
    If wind speeds in the Moore 99 tornado were measured at 318 +/-mph, then is it not logical to assume that Jarrell would be equal to that or more? Maybe I’m missing something or I don’t understand the complexity of a tornado as well as I think I do?

    • Thanks Jason! There’s a laundry list of tornadoes that have caused absolutely extraordinary damage, but I don’t think there’s any doubt Jarrell left behind the most complete destruction ever documented. Whether or not that translates to extremely high wind speeds is another matter. The fact is we really don’t have a good sense of what the max wind speeds in high-end violent tornadoes are, nor how they relate to particular instances of damage. Several violent tornadoes have been observed by mobile radar (Bridge Creek – Moore, El Reno, Red Rock, etc), but there have been hundreds of other violent tornadoes that go unobserved, so our sample size is really very small. It’s hard to draw any firm conclusions from a handful of data points.

      The other problem is that mobile radar (or any radar for that matter) doesn’t actually detect wind speeds. It observes the motion of hydrometeors and/or debris and derives a statistical range that can be used to estimate wind speed, so there’s always some uncertainty. The bigger issue is that those scatterers aren’t necessarily moving at the same speeds or in the same directions, and they also aren’t moving at the same speed as the actual wind. And we also don’t know for sure how the wind speed at the altitude the radar can observe (often ~100-300 ft. or so) translates to surface wind.

      So I guess that’s a long way of saying I have no idea, but I don’t think anyone else does either. As I mentioned above there is some truth to the slow movement debate, but I don’t think it accounts for everything. If I had to speculate I’d guess the max wind speeds were well above EF5 threshold, possibly 250-300+, but there isn’t much to base that on.

      • Do you think that a laser could be used to measure wind speeds or rather the scatterers in the funnel, near the ground?
        Assuming you were in a position to point it at the bottom 10 meters of the funnel, it would seem to me that a laser is focused enough to not be affected by the ground, unlike longer wavelength radio signals used in radar.

      • I seem to recall NASA’s Langley Research Center working on a method for using lasers to measure extreme wind velocities, so I suppose it’s possible. Aside from the obvious problems with deploying such equipment, I’d think the main difficulty would probably be the fact that the wind flow inside a tornado is extremely turbulent, full of eddies and wind shifts and complicated updrafts and downdrafts and such. There’s also new mobile radar technology being developed that should result in more rapid, fine-grained remote sensing.

    • Thank you Virgil, glad you like it. I should have a new post up in a day or two, it’s a lot of research so it’s taking a bit longer than expected.

  10. I’ve always been curious to know but since violent tornadoes tend to have stronger wind speeds higher up in the tornado, wouldn’t skyscrapers be more likely to topple or collapse due to the extreme winds higher up than when compared to ground levels? Skyscrapers generally can withstand very strong winds but higher up the winds are faster.

    • The wind speed does generally increase with height so it’s likely that a skyscraper would experience stronger winds, but they tend to be built very well. No skyscraper has ever been struck by a violent tornado to my knowledge, so it’s hard to say what would happen. The Great Plains Life Building in Lubbock, TX was struck by the F5 in 1970, but it was well south of the F5 damage and likely experienced lesser winds. I suspect a well-built skyscraper may withstand a violent tornado, but it would probably suffer some degree of structural deformation and possibly be rendered unusable.

    • It’s accurate, there were several mobile radars recording data on that tornado. The RaXPol radar recorded a maximum width of 2.6 miles and reportedly found velocities in excess of 132 m/s, or 295 mph. I haven’t seen 100% confirmation of the wind speed yet, but it seems to be in line with what I’ve heard so far. I think the more remarkable thing is that they found subvortices with a forward speed of 150+ mph. That’s just astounding. Unfortunately, it also sounds like that may be what caused the deaths of Tim and Paul Samaras and Carl Young.

  11. I know how some EF5 tornadoes can have brief gusts well over 250mph but is it possible for an EF5 to have sustained winds around that speed and is there any speculation to any tornadoes that may have had that? I think the Jarrell tornado might be one.

    • Good question, but it’s hard to say. It’s not hard to imagine there are extremely strong sustained winds in large or slow-moving tornadoes, but smaller or fast-moving ones probably wouldn’t be over a given area long enough for it to experience a one-minute sustained wind. And many of the most intense tornadoes are multivortex and/or have a complex structure, which complicates things further.

      I sure wish we had mobile radar data for Jarrell though, I think the data would probably have supported an F5 rating, even with the higher threshold on the old scale.

  12. My spouse and I stumbled over here coming from a different
    web page and thought I might as well check things out. I
    like what I see so now i’m following you. Look forward to looking over your web page yet again.

    • There’s no way to guarantee it, but the odds would have been better had those people had basements. It’s pretty rare for people to be killed in basements even in violent tornadoes, but considering the magnitude of the Jarrell tornado, it’s not hard to imagine that some people would have been killed even in basements. With all the airborne debris, dirt, etc., injuries likely would have been common as well.

      The only way to really be confident in surviving a violent tornado is to have a purpose-built safe room.

  13. I live in Dallas, but when I go to visit family in Kerrville (depending on which route I take), I sometimes drive through Jarrell on I-35 and always get such a haunting feeling as I totally remember that terrible tornado, although, to be sure, I was not there that day in May of 1997. I rememer it from the news. Such a sad loss of so many people. RIP all who died that day.

  14. My son was 17 when he lost his house in this tornado 17 years ago today. On that day he was at work in Temple and left work early because of weather warnings to get out of Temple. He got to Jarrell about 10 minutes after it was destroyed. He called me (I was in Houston) and said “Mom, the house is gone. Everything is gone.” He lived directly behind the Igos (family of five that were killed). We are still haunted by this. His house was rebuilt and he lived there for a short while and then had to move. He rents out the house.

    • Thanks for sharing, Nancy, I’m glad he wasn’t hurt. That must be a pretty terrible experience though nonetheless, especially at such a young age. This is one of the few tornadoes for which “everything is gone” is quite literally accurate. It’s very chilling to think about.

      • Thank you for your website. it gives an excellent description of the day’s events. My son’s house (slab) is the only B&W photo in the gallery at the end of your article.

  15. I will always remember this day as I sat next to the phone waiting for it to ring. Every year this day I pray for all those taken along with my brother. We have rebuilt but the 27 will always be in our prayers and remembrance.

  16. I was living in Austin at the time, as the storm moved south. By the time it reached my area, it was no longer tornadic, though the howling winds right outside my 1st story apartment made it seem otherwise. My neighborhood only lost power briefly, for less than a half hour, but I was listening to my portable cube-shaped with faux wood-grain NOAA weather radio, and I’d never heard such severe warnings and reports in my life; to say I was frightened is quite an understatement.

    Afterwards, tuning into a local AM talk radio station (KLBJ, 590 AM), where the typical programming was preempted by special reports about the weather, I heard numerous callers reporting their eyewitness accounts about the storms, including one man who had left work to go retrieve his family from their home that happened to be directly in the path of the storm. They were huddled in the closet when he arrived, and took their time finally answering the door. He said that he and his family escaped in the nick of time!

    Thank you very much for this moving and detailed article that serves to remind its readers of some of the poor souls that were lost, of the Igo, Ruiz, Moehring, and La France families. Until now I’d only read about various citizens of the affected area who’d perished, but this article provided a glimpse behind the morbidity statistics and revealed just how human they actually were. They all seemed like lovely people who died quite prematurely and horribly.

  17. Tornadoes are actually not uncommon in central Texas at all. There are many every year. But only the really major or significant ones get a lot of attention. Tornadoes happen all the way south into the Texas/Mexico Border and often into Mexico right off the high plateuas and mountains. The only reason why we rarely hear about them, is because of the sparsely populated region and towns are several miles apart and small. Most supercells that form along the Rio Grande into south Texas are quite large and very intense ,especially noted on radar. And radar has shown some rather extreme rotation in these storms rarely ever seen! There are likely more tornadoes in this region than we are aware of. But they happen in the middle of nowhere and nobody can reach then or see them. Who knows if 1 of these tornadoes happened to be the largest and most extreme ever. We will never know.
    As for the Jarrel Texas tornado, I have yet to see a tornado like that anywhere in this country or in Texas. This tornado was literally the definition of complete and utter destruction. Some report that this could have been apart of a military experiment of weather modification or (HAARP) which existed and they find it ironic when the Ft.Hood military base radar.went out and they couldnt see images on the radar for a time. They report seeing military jets around the storm and just before the storm moved in with beams and chemical agents being released. How true this is, remains to be a mystery. What are anyones thoughts on this?

    • Yeah, I touched on that above re: tornadoes in central/southern Texas and into Mexico. I wouldn’t say tornadoes are common, or at least not nearly as common as in the more traditional parts of “Tornado Alley,” but they certainly aren’t rare. It seems the Serranias del Burro region of Northern Mexico sees a couple of extremely intense, almost certainly tornadic supercells every year, though there’s practically nothing out there for them to hit. Every now and then they cross into Texas, though again there’s often not much in the way of structures. A situation like the 2007 Eagle Pass tornado is, thankfully, a rarity. Probably the most famous example of these large, violent supercells is the one that occurred on March 21, 2000. Here’s a radar grab (with labeled max velocities) as it reached its apparent peak, just west of Del Rio, TX.

      As for HAARP and other assorted things of that nature, I think there’s a whole lot of conspiracy and not much fact. Jarrell was certainly an exceptional tornado, but as you said just above, who knows how many other tornadoes have occurred in open fields that were just as intense as Jarrell? The meteorological processes that caused the tornado are (relatively) well-known, and in fact another less well-known example happened just two years later. The May 11, 1999 Loyal Valley, TX tornado occurred under broadly similar circumstances, and it was also extraordinarily intense. It just happened to occur in a sparsely populated area and only impacted a few homes. Such is the case with the majority of tornadoes.

      • I’m actually already doing research work right now in severe weather events, and this event is on the list. Do you think that there may be a correlation between these southwesterly moving tornadoes and them being immensely intense? The shear would definitely align in a much different manner than a typical east or northeasterly moving tornado or super cell. This type of unusual movement may create a much more vigorous rotation that otherwise thought. Ill have to continue in this research.

  18. By the way that radar shot of the Del Rio storm is exactly what I mean when I say extreme! That is a very tight intense couplet. I get my radar from past events from the NCDC where do you get yours from?

    • I’m gonna answer both of your posts here since I can’t reply directly to the first one. Anomalous storm motion can definitely have significant effects on a storm, but I’m not sure the correlation is quite so direct. What highly deviant motion CAN do is set the stage by making the near-storm environment much more favorable for tornadoes, and significant tornadoes, than might otherwise be expected. That’s one of the things that makes right-moving supercells so key as far as tornado production, but that kind of motion just takes things to the extreme.

      So in a situation where a typical northeasterly storm motion might yield a lackluster storm-relative helicity of, say, 100 m²s², a southerly or southwesterly storm motion might yield four times that depending on exactly what the shear vector looks like and so on. That in itself won’t produce a violent tornado, but it can certainly make it more likely. It also tends to produce much slower storm motions, so if a tornado forms the residence time over a given structure can be much greater. The connection between forward speed and damage is rather complex and not well-understood, but it’s probably safe to assume that 200 mph winds for several minutes is going to do considerably more damage than those same winds for 15 seconds.

      Also, yes, I use NCDC’s HDSS access system to download L2 data. It’s an excellent resource. And I agree, that radar signature is just about as textbook as you can get; it seems a little strange to see that kind of signature all the way down in Mexico, but you can pretty much count on a couple of those almost every year in that region. Storms develop in the lee of the Serranias del Burro and just explode into monster tornadic supercells in no time. It’s very fortunate that there are almost no buildings or people there, but it’s a shame that there’s virtually no scientific data or observations on what really goes on out there in the desert.

      • Yeah I thought the same thing about those southwesterly storms. As for the slow movement and relation to extreme damage, it can certainly have an impact on the amount of damage, although this tornado had very distinct extreme cases as you’ve already said. And yes I agree they should be investing money in the northern 1/2 of Mexico since quite a few of Texas spring storm system move directly out of Mexico. I hear a lot of meteorologists on TV and the NWS always talk about how difficult it is when trying to forecast severe weather events or weather period for systems moving out of Mexico, since there’s no data or observations coming out of there. In my honest opinion this can really cut down on the amount of surprise outbreaks in Texas.

  19. You can look on Wikipedia for ‘2000 Forth Worth tornado’ and see a skyscraper after it took a direct hit. This building was scheduled to be demolished right about the time of the 9/11 attack. Because of the 9/11 incident, they waited and waited. Early reports noted significant structural damage. But after more assessment they believed it was structurally salvageable. It still stands to day. The cost to renovate a high rise hit by a tornado can be prohibitive even if it is structurally safe. This was not a particularly strong tornado at all.

    • I never heard of it needing to be demolished. But this was a strong tornado as anyone could see by the extensive amount of damage not just to this high rise building ,which is supoossed to be much stronger than any average building, but also bad damage to homes, and businesses.

  20. Excellent analysis of this tornado – I like your narrative how you combine story with meteorological facts – makes interesting reading. I hope that you can do an analysis of the Joplin tornado or even a Intro on how tornadoes form with some graphics. There’s stuff out there but nothing concise or written in a way that makes it understandable to non meteo types

  21. One thing to always remember, is that debris kills and does damage, the wind only offers a means of travel for the debris. Human beings have been tested in wind tunnels with 300 mph winds, and other than a very very distorted face, and not being able to move much at all, it does not harm people. But in the real world, a tornado is a giant sandblaster. It throws cars, tractors, trucks, trees, and everything in its path like wrecking balls every which way. Not very many homes can withstand an object with the weight of a car impacting them at speed. Gravel and sand will eat away at everything

  22. About a year or so after the tornado, I spoke with an older gentleman who lived just west of Double Creek, and up a hill. He and his wife watched the entire thing unfold. Quote: “It was the scaredest I’ve ever been in my life”. And when a man tells you that with the look he had, you tend to give it a significant amount of weight. He also said, as the tornado dissipated, apparently this happened over a rock quarry, and he said it went “chalk white”. I’ve never read this anywhere else in accounts of the storm. I had picked up a heavy gauge piece of roof metal that was compressed to a size of maybe 14 inches by 24 inches, and it had 17 small penetration holes where something had blown through it…almost as if it had be blasted with a shotgun, but various in size from BB to I’d say a quarter. To imagine the wind ripping that metal down to that size, and blasting it with debris like that is just unimaginable when you factor humans into the beast…

    Thanks for the story Shawn…awesome to the nth…

  23. The Sherman F5 tornado of 1896 may have been of at least similar intensity to the Jarrell tornado. It did not take on the shape of a wedge tornado which is typical of most F5 or EF5 tornadoes. An iron bridge weighing hundreds of.tons was pulled from its support beams and torn into several pieces and deemed by survivors as “useless scraps.” Houses were blown into atoms, the ground was so scoured it looked like it had been taken up by a till, railroad tracks were ripped off the ground, headstones at a cemetery were pulled out of the ground and thrown almost a quarter of a mile, bodies were found over a half mile away and mangled beyond recognition, and a trunk lid was found over 35 miles away. It was almost rope like when it caused its most intense damage.

  24. This site is very informative, and explains things in a way that is understandable to most people. Well done. The Jarrell tornado is an event that has always fascinated me. From the uncommon development of the storm, to the rapidly intensifying circulation almost directly over the Double Creek area, something about this particular tornado will just not allow me to let it go. Perhaps the complete and utter devastation is what makes this instance so unfathomable. To imagine a monster such as this essentially hovering over a neighborhood with a forward speed anywhere from 8-10mph (check accuracy please), it isn’t hard for one’s mind to wander. That being said, it isn’t a surprise to me that I’m quite addicted to tornado stories, facts, and the like as I live in the state tied for 2nd place with the most (E)F-5’s, that being Iowa (actually tied for 1st if you include the 1893 Pomeroy, Iowa incident as an F-5) with 6 confirmed. The most recent beast from the hawkeye state being the Parkersburg/New Hartford 2008 incident, this event seemed almost unreal, as the last F-5 to strike Iowa before that was the “Jordan” (Boone County) event of 1976, well before I was blessed with existence. The Jordan tornado is particularly curious to me, as not a whole lot of credulous information seems to exist about an event studied by the like of Dr. Fujita himself. That storm stirs interest deep within me, much like Jarrell, as it not only produced an incredible F-5 tornado, but also spawned an anti-cyclonic F-3 satellite twister not far from the main stovepipe. To boot, as I was reading over eyewitness accounts and stories from that day, the main tornado was also said to have yet another orbiting satellite vortex spiraling around it as it dredged toward Jordan. I was curious what kind of information you might be able to blow the dust off of regarding this particular incident, as even though it occurred around 30-40 miles from Des Moines, the largest metro area in Iowa, not much info seems to exist about it. You seem to know what’s what regarding these events, thus leading to my inquiry. Great site!

  25. I was living in Austin when this tornado hit it still haunts me today. And I have found the names of 21 victims Vicki Taylor,Jonathan Kehl, Michael Carmona, The Gower Family The Igo Family Billy LaFrance The Moehring Family, John And Michael Ruiz Maria Ruiz And The Smith Family there are 6 people missing possibly 2 children and 4 adults. I am trying to add the correct people to Find a Grave as a memorial. Can Someone please help me with the missing people. I believe everyone should be included in this memorial.

  26. Pingback: The 20th Anniversary of the Jarrell, TX EF-5 Tornado

  27. So I have a couple questions. 1) People claim this was a slow moving tornado and that’s why the damage was so extreme. Except the math shows otherwise. It was on the ground for 10 minutes and traveled 7.6 miles. That’s an average velocity of 45mph. So, how exactly did they derive single digits here? And 2) Sandblasters produce wind speeds of over 1000mph. They can remove skin and disintegrate things much like the Jarrell tornado did. We’ve never seen that kind of damage in any other F5 tornado. Wouldn’t it seem probable that the winds here were a lot higher than the ‘F5’ threshold?

    • The tornado was on the ground for roughly 45 minutes in all, though it’s hard to know exactly how long since the precise time of dissipation isn’t known. That’d put the average forward speed at a shade over 10 mph. Witnesses also estimated that it traveled at 5-10 mph, though I’d take that with a grain of salt. It’s also important to remember that the forward speed can (and frequently does) vary over the length of the path.

      Either way, I don’t think that fully accounts for the incredible intensity of the damage. We’ve had plenty of examples of violent tornadoes moving very slowly (albeit rarely through populated places, thankfully) and yet few of them even approach the violence of Jarrell. I don’t think there’s any question we’re talking about a top-of-the-scale sort of tornado with respect to wind speed.

      ‘Course, that still leaves the question of what “top-of-the-scale” really means, and I’m not sure we know enough to answer that. We know that ~200 mph is sufficient to cause tremendous damage, but we also have pretty good evidence that tornadoes are potentially capable of producing velocities exceeding 300 mph. I’m inclined to believe Jarrell’s max wind speeds were well into that range, but I don’t have any hard evidence to base that on.

      Regarding sandblasters, there are very different physical processes going on there. Sandblasters accelerate small grains to those kinds of incredible speeds over very limited areas and in more-or-less linear paths. In a tornado, you have a tremendous volume of air (loaded with truly massive amounts of debris, ranging from sand/dirt grains up to vehicles and such) moving over a large area. And not only moving but also rapidly shifting directions both horizontally and vertically. Consider, too, that the force of wind isn’t linear – it increases with the cube of the wind speed. All of that together adds up to an unbelievable amount of destructive potential.

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