Tornado Alley The Storm That Defied The Odds Mega Disaster Episode 3
What happens when the most intense tornado ever measured strikes Dallas, Texas? With winds clocked at 318 miles per hour, the monster twister carves a path through the city up to a mile wide. It happened once before, just two hundred miles to the north in Oklahoma City. There in May 1999 a "Megatornado" scoured the earth for 85 minutes along a 38-mile path.
Combining science and history, Mega Disasters visits the sites of the most incredible disasters of the past -- and then virtually recreates them in modern times and locations using state-of-the-art computer animation.
Documentary Central is the home for compelling documentaries tackling subjects like history, climate change, wildlife, conspiracy and more.
Combining science and history, Mega Disasters visits the sites of the most incredible disasters of the past -- and then virtually recreates them in modern times and locations using state-of-the-art computer animation.
Documentary Central is the home for compelling documentaries tackling subjects like history, climate change, wildlife, conspiracy and more.
Category
📺
TVTranscript
00:00Wow! What a tornado!
00:03Tornadoes are unpredictable.
00:05Back the f*** up!
00:07Volatile.
00:09The whole country looked like it was in a nuclear blast at some time.
00:14And lethal.
00:15I kept talking to myself thinking, well, this is it.
00:19They leave behind obliterated towns.
00:21There were no houses left. They were all gone.
00:24And bewildered scientists.
00:26It's not an exact science.
00:28Each tornado is unique.
00:30Most dangerous. A few deadly.
00:33From the tremendous to the terrifying to the tragic.
00:36This is a countdown to a mega tornado.
00:39One that experts believe will devastate a major American city.
00:58The most ominous tornado warning comes when an apocalyptic-like darkness fills the sky.
01:05These clouds are precursors to a powerful storm.
01:09A supercell.
01:12Most tornadoes form when a violently rotating column of air stretches down from that supercell to touch the earth.
01:21In general, the faster the wind speeds, the more dangerous the tornado.
01:27Surprisingly, relatively little is known about these giant killers.
01:33Scientists are literally chasing the mysteries of tornadoes across the great plains of the United States.
01:39Better known as Tornado Alley.
01:45More than 400 tornadoes threaten to wreak a path of destruction here every year.
01:51Far more than any other place in the world.
01:55The main reason? Ideal atmospheric conditions.
01:59The mountains to the west, the Gulf of Mexico to the south,
02:04and the fact that there are no physical barriers between here and the North Pole
02:10means that we are frequently changing air masses from warm to cold and back again.
02:16Tornadoes are measured using the F-scale.
02:20F for Dr. Theodore Fujita, who classified tornado strength by estimating wind speed based on devastation.
02:28The smallest twisters are F0s.
02:31They can reach 116 km per hour, about the equivalent of a small hurricane.
02:37At the other end of the scale are F5s, whose winds reach speeds of up to 512 km per hour.
02:44Bigger! Bigger!
02:47Keep going, keep going, keep going!
02:49The tornadoes profiled here rise up the Fujita scale,
02:52from an F2 that rips the roof off a house,
02:55Did you see that?
02:57to an F5 that lays waste to an entire neighborhood.
03:02It's all leading up to a mega tornado,
03:05one that some scientists fear will ravage a primary city.
03:15The Big Tornado
03:25111 km southwest of Wichita lies the small town of Attica, Kansas.
03:31Just over 600 people live here.
03:34It's a town you could easily miss.
03:37On May 12, 2004, a tornado didn't.
03:43On that day, the blue skies over Harper County fill with storm clouds.
03:50Shortly after 6 p.m., Dan Smith Eisler heads into Attica.
03:55I did some work for the banker in there,
03:59and I told his wife, I said, you know, it's going to storm today.
04:04Several thunderstorms form over southern Kansas.
04:07One look at these storms tells 30-year veteran meteorologist Chuck Doswell
04:11they might be a breeding ground for tornadoes.
04:14One of the important ingredients that produces a tornado that we're pretty sure is
04:19the wind at low levels has to change direction and speed rapidly with height.
04:26We call that vertical wind shear.
04:29The vertical wind shear typically spins the air into an invisible cylinder.
04:34As the wind speed increases and rises,
04:37the tornado intensifies and the core pressure drops.
04:41Condensation from the dropping pressure builds down the funnel,
04:44creating a visible tornado.
04:48That's exactly what's happening in the southern Kansas sky.
04:53Harper County Emergency Management Director Mike Loregg
04:56gets the first tornado warning at 645.
04:59And when they start giving us those warnings, we listen and we say,
05:02hey, we need to start warning our public from there.
05:05We do not know if this is going to be an F-0 or it's going to turn into the monster.
05:12In Kansas, meteorologists carefully follow the thunderstorm as it tracks towards Attica.
05:18About 725 in the evening, a F-2 tornado had made it to ground right up here just on this hill.
05:27The path of it was right across here.
05:30As Loregg watches in astonishment, the tornado tears the roof off a home directly in front of him.
05:36Oh, my God! Oh, my God! The whole house came apart!
05:45This act of violence is just one of many.
05:49The angry skies over Kansas are far from finished.
05:53We thought, OK, hopefully things are over.
05:56We've got emergency crews set up for that.
05:58And then the storm just suddenly took a life on its own.
06:04Storm chasers tracking the Kansas supercell relay information to meteorologists using mobile Doppler radar.
06:12They report the tornado's wind speed, location, and one other startling fact.
06:17The storm is producing multiple tornadoes.
06:21Look at that.
06:23Storm chaser Yvette Richardson's seen a supercell create more than one tornado before.
06:28It can be a very dangerous situation because often people will be looking at the main tornado
06:35and feeling that as long as they're far enough away or they've taken cover, that they should be completely safe.
06:44Her team and others report seeing 16 tornadoes.
06:48They vary significantly in size and power.
06:52The biggest is an F-4, roughly 160 kilometers per hour faster
06:56and with corresponding wind force about three times larger than an F-2.
07:01The F-4 heads straight for Dan and Donna Smith-Heisler's home.
07:05I was listening to the radio and the TV, and they had it exactly pinpointed.
07:10They knew exactly where it was at.
07:13Knowing a tornado's path gives potential victims an average of 12 minutes warning,
07:18enough time to save their lives.
07:22The Smith-Heislers get the warning, but Dan ignores it.
07:27Mesmerized by the golf ball-sized hail that often precedes a tornado,
07:32he refuses to join his wife down in the basement.
07:36That scared me, and so I started screaming at him to get down.
07:38The dog would not come down.
07:40He said, well, sugar won't come.
07:42And she was going in the door, out the door, in the door.
07:45Dogs are smart. They know.
07:48So when I screamed at sugar, then she came down, he came down.
07:51We started hearing this popping noise.
07:53Well, we had a rack of canned goods over there.
07:56And those cans were popping from the pressure change.
07:59It sounded like popcorn was going off over there.
08:03The tornado batters Dan and Donna's home,
08:05with winds estimated at more than 322 kilometers per hour.
08:10And that's when I got hit on the head with cement or something, you know.
08:14I can still hear myself groan.
08:18All of a sudden, you're just going to, like, go with it.
08:20And that's where I was when he said, we're not going to make it.
08:23And that woke me up, and I said, oh, yes, we are too, you know.
08:26And you pray really hard.
08:29The savage winds rip unrelentingly over the Smith-Heislers' home.
08:39When they finally stop, the couple emerge from their basement and into a war zone.
08:47And I thought, where's the car?
08:50And then my next thought was, where's the garage?
08:55The twister destroyed the couple's two-story home, five barns,
08:59dismantled five cars, and killed their dog, Sugar.
09:03The terror down there was the worst part, the terror.
09:09The Smith-Heislers are lucky to be alive.
09:11With estimated wind speeds near 400 kilometers per hour,
09:15the F4 tornado easily destroyed their home.
09:20But even the earlier F2, with winds estimated at 240 kilometers per hour,
09:25was capable of ripping the roof off this home.
09:29Complex physics transform air into a lethal force,
09:34a concept scientists are laboring to understand.
09:38What we are trying to do is simulate the tornado as best as we can.
09:42So we're actually comparing the wind which we generate here
09:45with the measurements made in the field.
09:48And the match is pretty good.
09:51Sarkar's tornado simulator is the first of its kind in the world.
09:55It uses dry ice to create a visual display of the wind inside a vortex.
10:01His machine can produce tornadoes up to 1.2 meters in diameter
10:05and 2.4 meters tall.
10:07It can reach peak wind speeds of 86 kilometers per hour.
10:11When combined with scale models, he's able to replicate damage
10:15much larger and faster tornadoes inflict on homes and other structures.
10:21Normally a portion of the roof fails and creates a hole in the building
10:24which then the flow starts getting inside,
10:27which then creates more load on the walls,
10:30and eventually those walls start failing.
10:33Sarkar's experiments conclude that the destructive force of circulating wind
10:37in an F3 or stronger tornado is at least three times more powerful
10:41than straight-line winds.
10:44Since few structures in Tornado Alley are designed to withstand
10:47even an F1's winds, this is stark proof that even the weakest tornado
10:52is capable of causing damage.
10:56The residents of Attica were thankful to have survived the fury
10:59of the 16 tornadoes that struck southern Kansas.
11:04But when a single F4 twister strikes a small Texas town,
11:08its bizarre behavior and surprising power threatens to destroy the entire city.
11:16And later, a mega-tornado strikes a major American city,
11:20something experts say will happen.
11:25In 2004, a single Kansas storm produced a swarm of tornadoes
11:30that ravaged homes, destroyed property, and terrorized hundreds.
11:37But the power and damage of that outbreak was far surpassed
11:40by the stunning force and unpredictable behavior of a single Texas twister.
12:03Pampa, Texas has had its share of luck.
12:08The town has prospered since oil was discovered here in 1921.
12:13Today, 17,000 residents work the hard soil, farming, ranching, and refining oil.
12:21But the town's location in the Texas panhandle is also its biggest flaw.
12:25This is tornado country.
12:31On the afternoon of June 8, 1995, Pampa's luck ran out.
12:38Randy Stubblefield is a lifelong resident of Pampa.
12:42In his two years as sheriff, he's seen his share of violence.
12:46But nothing compares to what he's about to confront.
12:50About 4 o'clock in the afternoon, we received a call that there was a large tornado
12:54that was building on the south side of the Emerald Highway,
12:57just about a mile and a half from where we're standing now.
13:04Stubblefield grabs his camcorder and rushes towards the twister.
13:08I watched it building on the farmland on the north side of the railroad tracks,
13:13and it just started building, getting bigger and bigger.
13:16Meteorologist Chuck Doswell is also chasing and filming the Pampa tornado.
13:21The evolution of the Pampa tornado with respect to the parent thunderstorm
13:27was very unusual in my experience.
13:30I've never seen anything quite like it.
13:33What Doswell sees is remarkable. The tornado is almost standing still.
13:38It's impossible to tell what's going on in there.
13:40Then, suddenly, the tornado makes a sharp right turn.
13:44This odd behavior stuns Doswell.
13:47Tornadoes move in a particular direction because they're tied to the storm that's producing them.
13:53And the storm that's producing them moves in a particular direction
13:56because it's embedded in a wind field which is pushing it in that direction.
14:01But the Pampa tornado isn't moving in the same direction as the storm.
14:05After a series of sharp turns, the twister loops almost 270 degrees around Doswell.
14:12These erratic and unpredictable movements make this a very dangerous tornado.
14:17Let's go.
14:19And I am completely mystified as to what was going on with that storm.
14:24Then it started traveling north.
14:26Get everybody inside because this is one big son of a...
14:29It hit an industrial complex.
14:38Belinda Waldrop works in that complex with her father.
14:41She isn't listening to the news.
14:43I learned that there was a tornado outside the building
14:48when my dad came to the door of the office I was in and said,
14:52Belinda, there's a tornado on the ground west of us.
14:55I'm curious. I said, can we look at it?
14:58And he said, oh, no, we don't need to look at it.
15:01We need to get under some cover.
15:05Belinda and her father die for shelter as the twister slams towards them.
15:10You could hear the tornado approaching.
15:15It was like a gyrating woof-woof,
15:18just a churning that just got gradually more intense and louder.
15:26The lights began to flicker as the pressure was building,
15:30and then the lights went out.
15:35Whenever you first start seeing the real debris, the metal, the rooftops and all that,
15:39that's when it hit the first series of steel buildings in the industrial complex.
15:47And then an explosion.
15:49The vacuum just took me up off the floor and slammed me into numerous things
15:55and was pulling me backward like a ragdoll.
16:03You're going to see some vehicles going into the air,
16:07transport trailers and truck combinations.
16:09Now, these units weigh probably 22,000 pounds empty.
16:13These were sucked up and in the tornado
16:16and were going round and round.
16:18Stubblefield and Oswell are among the few to ever film a tornado
16:22snatching out three-ton trucks.
16:25This is a massively powerful twister,
16:28one that has Belinda Waldrop trapped in its ferocious grip.
16:32When I was in it, everything's dark,
16:35and I just tried to keep my eyes closed to protect my eyes.
16:39I kept talking to myself, thinking, well, this is it.
16:43And at that time, I just had a feeling of helplessness
16:45because there's nothing you can do.
16:47I mean, there's no way you can stop it, you know,
16:49or make it go in other directions or anything like that.
16:51And it was just a sick feeling.
16:53That dropped me out here into the parking lot
16:56and just dropped me on my back,
17:00and I could see the cloud and the tornado.
17:02It looked like a white ghost just going up and taking off.
17:08Belinda's encounter with the tornado is one of her most memorable.
17:12Belinda's encounter with the tornado is over,
17:14but Randy's is just beginning.
17:16But when I realized that it was going to go into the city of Pampa...
17:19Stubblefield jumps back into his car and races down the road,
17:23directly into the path of the tornado.
17:26One of my deputies gets on the air and says,
17:28watch out, you're too close.
17:30Hey, careful, you're almost there.
17:32You know you're too close when debris starts coming in the car with you.
17:35I had my windows down, and the trash from the circulation
17:37was coming into the car with me.
17:39It's going into the city at this time.
17:41I headed right straight for the sheriff's office in the downtown section.
17:44Well, I had, at that time, about 65 prisoners in jail.
17:48And, you know, we had a big, strong building,
17:50but this big, strong tornado.
17:52The twister strikes Pampa,
17:54destroying or damaging 200 homes and 50 businesses.
17:58Most buildings in the industrial park are ripped off their foundations.
18:02Belinda is badly injured and in shock.
18:07Of course I was just stunned and numb.
18:10I really couldn't feel anything.
18:12I felt like my legs were probably broken.
18:14I couldn't get my bearings because there was no building.
18:18There were no landmarks that I recognized at all,
18:21and I was just taken back.
18:23Fearing the worst, Belinda desperately searches for her father.
18:27He was draped over a motor.
18:29He looked dead, honestly.
18:31He was limp, and he wasn't moving.
18:33I managed to scoot over close to him and started rubbing him.
18:38He woke up and turned his head, and there was blood,
18:41and you could just see this white eyeball.
18:45Just a terrified look, and I'll always remember that, just stark.
18:50And he immediately said,
18:52Help me up, help me up, and I said,
18:54I can't help you up. I can't get up either.
18:57Emergency workers rush Belinda and her dad to the hospital.
19:01Both are in serious condition.
19:03Five other residents also suffer injuries.
19:06Miraculously, there are no deaths.
19:10As the wounded begin their recuperation,
19:13experts study Stubblefield and Doswell's remarkable footage.
19:17To tumble a two- or three-ton pickup truck
19:20along the ground and then hoist it in the air,
19:23this takes incredible wind speeds,
19:25probably in excess of 150 miles per hour.
19:28Dave Llewellyn researches the strange and complex forces
19:32at work inside tornadoes.
19:34In a tornado, the wind is not just swirling around.
19:37It's actually spiraling strongly inwards.
19:40Llewellyn believes that once an object like a vehicle is airborne,
19:44it can be slammed to the ground by powerful center downdraft winds,
19:48then hurled back skywards by updraft winds.
19:51This brutal cycle renders the debris unrecognizable
19:55before it's finally spat out as a high-speed missile.
20:05Amazing. That was 4,600 pounds thrown into the crane.
20:09Scott Schiff and his team at Clemson University
20:12are studying the damage a tornado-hulled car can do.
20:16We're really testing this roof slab here,
20:20and this was designed to be a shelter.
20:22It's about 10 inches thick of solid concrete
20:25with a double mat of steel reinforcement,
20:27so it's heavily reinforced.
20:29It's really designed to be able to take large debris impacts.
20:323, 2, 1, drop!
20:40After multiple impacts, the slab begins to crumble.
20:48So after that last impact,
20:50we now have a permanent deformation in the slab.
20:53That rebar that's down under that bottom mat there
20:56started to yield under the load,
20:59and we started to see some more concrete falling down below there.
21:02To counter multiple impacts,
21:04Schiff is designing a steel mesh net to catch loose debris.
21:08If that works, it will be a huge step forward in tornado protection.
21:12We have this terrific F5 tornado.
21:15What we're looking for is that we are safe
21:18during the event and right after the event.
21:23Despite the Pampa tornado's unpredictable movements
21:26and incredible power, no lives were taken.
21:30608 kilometers away, another Texas town isn't so fortunate
21:34when a massive F5 twister turns tiny bits of dirt and wood
21:38into lethal weapons.
21:42And later, a mega tornado,
21:44one that scientists believe could destroy a major American city.
21:51The powerful F4 Pampa tornado tossed trucks,
21:54destroyed buildings, and threatened the lives of hundreds.
22:00But just one notch up the Fujita scale,
22:03an F5 twister turns into a killer.
22:06Its weapons, specks of dirt and splinters of wood.
22:25Gerald, Texas was founded in 1909.
22:29Located 64 kilometers north of Austin,
22:32the town never fully recovered from the decline of the cotton industry
22:36in the 1920s and 30s.
22:38In 1997, a tornado threatened to wipe Gerald off the map.
22:47From the beginning, the Gerald tornado smacks of something strange.
22:52On May 27th, a supercell forms over central Texas.
22:56The Gerald tornado is memorable for a couple of things.
22:59One was it was a... it formed in conditions
23:02that at the time we thought were very unusual.
23:05The massive supercell lacks strong vertical wind shear,
23:08an essential ingredient in typical tornado formation.
23:13Meteorologist Bill Gallas teaches tornado forecasting,
23:16utilizing a virtual reality tornado simulator.
23:19To get a tornado in nature, you need to have really two things.
23:23You need a very strong updraft, or updraft and downdraft,
23:27to help stretch the air in the vertical.
23:29And you also need to have some source of spin present.
23:33Strong wind shear usually provides a tornado with its source of spin.
23:38Before Gerald, the conventional wisdom was that without strong wind shear,
23:42you don't get violent tornadoes.
23:45But the unusual atmospheric conditions over central Texas
23:48are about to prove the conventional wisdom wrong.
23:51Dead wrong.
23:54Here, the warm moist air rises so forcefully,
23:57it generates a super strong updraft,
23:59creating a very powerful and dangerous tornado.
24:07As the skies blacken and the winds rage,
24:10As the skies blacken and the winds rage,
24:13LaDonna Peterson and her 8-year-old son
24:15leave their mobile home for the safety of her mother-in-law's brick house.
24:19I went outside and started watching the clouds outside
24:22because they were getting real thick, real dark, real heavy.
24:25And all of a sudden I could hear in the distance,
24:28because the wind had picked up, the alarm going off in town.
24:34Ken Adams doesn't hear the town alarm.
24:37He's asleep.
24:39And the dog woke me up,
24:41and I could tell that dog was really scared.
24:44I knew something was wrong, but I don't hear well,
24:47but I could feel it.
24:49It was like a thunder that you couldn't hear,
24:53you know, but you could feel it.
24:56LaDonna's sister-in-law and young daughter
24:59join her in their mother-in-law's home.
25:01News reports place a tornado 3 kilometers away.
25:05My sister-in-law and I went to a window,
25:07and we could actually see the tornado in the distance,
25:10but it was like it was just sitting there, just turning, not moving at all.
25:14In fact, the tornado isn't standing still.
25:17Its forward movement is clocked at a slow pace of 16 kilometers per hour.
25:23But its internal wind speeds are reaching more than 420 kilometers per hour.
25:29Now a killer F5, it descends on the women's refuge.
25:33Then all of a sudden we felt a gust of wind hit the house.
25:36We could actually see the asphalt being pulled up off the street, up the road from us.
25:42We were sitting there, and I said, God, please don't take my family.
25:45Then we felt a big gust of wind hit the house,
25:48and the bathroom door flew open,
25:50and at that point we just started feeling like mud and stuff start coming in, hay.
25:55Minutes later, when Ken Adams walks outside to see why his dog is barking,
25:59he comes face to face with a nightmare.
26:06It was so big at the base, probably a half a mile or three quarters of a mile,
26:11that I didn't realize it was a tornado,
26:14and by the time that I did realize it, it was too late to go anywhere.
26:20I ran to the house, opened the back door,
26:23and as I did, the door flew out of my hands,
26:26and the roof of the house came off.
26:30I would sort of be picked up. The house would fall on me again.
26:36Suddenly, the tornado is gone.
26:39The whole country looked like it was in a nuclear blast of some type.
26:44When I first looked up, I thought I was dead. I mean, I really did.
26:49Ken is wrenched back to reality when he's forced to take in the horror that surrounds him.
26:56More than 300 head of cattle were killed or injured by the tornado.
27:00Many that survived had to be shot because of the extent of their injuries.
27:06Oh, it was terrible. There's about 300 acres over there,
27:09and most of it, you couldn't walk very far without smelling that old dead smell.
27:15LaDonna's family emerges from the rubble of their home and into a wasteland.
27:20Nearly every home in their subdivision is obliterated.
27:23Many of their neighbors are nowhere to be seen. Others are badly injured.
27:28Mrs. LaFrance was pinned under a tree, and her daughter was laying in the mud
27:33and had some really severe injuries to her legs and her arms.
27:38It was raining, and she was saying it was hurting her, hitting the open wounds,
27:41so the only thing I could find was a dirty blanket laying on the ground to cover her up with
27:45just to keep the rain from hitting the wounds so bad.
27:48Later, we found out that Mr. LaFrance had been killed in the tornado,
27:51and the daughter had been crying through the whole thing, wanting to know where her dad was.
27:58Twenty-seven people died that day. Half were children. Entire families killed.
28:15As scientists studied the Jarrell tornado, several intriguing facts came to light.
28:21The thing that the tornado itself was interesting for was that it was moving very, very slowly,
28:26and it was large, and it collected a lot of debris to where the high wind speeds
28:30associated with the tornado were there for minutes in locations rather than just for a few seconds.
28:37The tornado traveled approximately 16 kilometers per hour,
28:41significantly slower than the average 48-kilometer-per-hour twister.
28:46Another oddity was that most houses in the tornado's path were completely obliterated.
28:51After much study, experts found an answer.
28:57Physicist Dave Llewellyn's computer models illustrate their findings.
29:01You can actually have thousands of tons of dirt in that debris cloud at any given time,
29:08and that dirt can change the internal structure of the tornado.
29:12As the Jarrell tornado passed over the open Texas plain, it picked up massive amounts of dirt,
29:18slowing down the funnel's forward movement while increasing its destructive power.
29:23I think down low that Jarrell tornado probably acted like a giant sandblaster.
29:28Llewellyn and others believe that instead of blowing apart homes with strong winds like some tornadoes,
29:34the Jarrell twister destroyed structures via the massive force of windblown debris.
29:43The Jarrell tornado was as ironic as it was tragic.
29:47Experts advise never to try and outrun a twister,
29:51but some who died in Jarrell could have escaped the slow-moving storm in cars.
29:57Experts advise potential victims without storm shelters to hide in interior rooms like closets or bathrooms,
30:04but some in Jarrell did exactly that and died anyway when their entire home was swept away.
30:11Still, because no two twisters are ever the same,
30:14experts advise that the best option is an underground shelter or safe room built to specific codes.
30:23The Jarrell tornado changed the way experts watch for twisters.
30:27They now view storm systems with low vertical wind shear as possible violent tornado producers.
30:34But no amount of vigilance or insight could stop the deadliest tornado in US history from killing hundreds.
30:42And later, a mega-tornado unseen in modern times threatens millions.
30:50The Jarrell twister killed 27 people while changing the way experts keep vigil for potential tornado-producing storms.
30:59But there was no way to prepare for the deadliest tornado in US history,
31:03a brutal F5 that tore through three states, killing hundreds.
31:16On March 18, 1925, a single tornado slaughtered 695 people in Missouri, Illinois and Indiana.
31:25The behemoth F5 blasted a 322-kilometer path of unstoppable annihilation that lasted for hours.
31:33Survivor accounts are chilling.
31:36The air was filled with 10,000 things, boards, poles, whole sides of little framed houses.
31:42In some cases, the houses themselves were picked up and smashed to the earth, and living beings too.
31:48A baby was blown from its mother's arms.
31:51Children all around me were cut and bleeding.
31:53They cried and screamed.
31:55It was something awful.
31:58The destruction was of mythic proportions, primarily because the killer struck an extremely vulnerable population.
32:05People had very few ideas about how to deal with tornadoes.
32:09The country was largely rural instead of mostly metropolitan,
32:14and they had essentially no way to communicate with each other.
32:18The town of Murfreesboro, where more than 100 people were killed,
32:22actually was hit more than two hours after the first fatalities from the tornado.
32:27And people wondered, why hadn't any word gotten downstream,
32:31down the telephone lines or telegraph lines, that something was coming?
32:35In 1925, several million people lived in small rural towns throughout Tornado Alley.
32:41Today, tens of millions call it home.
32:45Modern communication means better warnings,
32:48but evacuating a major city before an F5 strikes is still impossible.
32:54On May 3rd, 1999, the people of Oklahoma City faced the worst F5 in modern history.
33:14The May 3rd, 1999 tornado that went through Moore in southern Oklahoma City
33:18was one of the most damaging in the history of the United States, no matter how we look at the data.
33:25Late in the afternoon of May 3rd, 1999,
33:28weather forecasters in Oklahoma carefully track multiple supercell storms,
33:33and then the tornado reports that begin flooding in.
33:36At home with her eight-year-old son, Dana Grimm watches the local news.
33:40We had been watching the coverage for hours.
33:42He said it just kept building momentum, getting bigger and bigger,
33:45and if you were above ground, you weren't going to make it.
33:48The storm system is intense, complicated, and growing.
33:52Weather trackers watch in awe and shock as multiple storms produce multiple tornadoes.
33:58The storm system is intense, complicated, and growing.
34:01Weather trackers watch in awe and shock as multiple storms produce multiple tornadoes.
34:06Large tornado, very large tornado.
34:09It seemed like just about every thunderstorm cloud that formed
34:13eventually produced a tornado at some point.
34:17And there were times when you had the main tornado happening,
34:21and then we had what we call satellite tornadoes that would rotate around it.
34:26And they're completely separate tornadoes within the same storm system.
34:32At about 6.25 p.m., a large tornado touches down just outside Amber, Oklahoma.
34:42Doppler radar records its wind speed at 512 kilometers per hour,
34:47the fastest twister ever documented.
34:50This is a monster, and it's hurtling towards Dana Grimm's home.
34:54And they had said that it was a mile wide and just ferocious,
34:58and it was just destroying everything in its path.
35:04With a giant wall of howling wind just 1.6 kilometers away,
35:08Dana and her son hide in a closet.
35:12I remember my son, he was screaming and crying.
35:15He said, are we going to be okay? I said, we're going to be fine.
35:18He said, what do we do? And I said, we pray.
35:22Dana's fear turns to panic when she hears the tornado strike.
35:29There was kind of a high-pitched squeal to it.
35:34And then, of course, the sound of everything, the windows just blowing out.
35:40The house was shaking. We could hear the beams in the roof breaking.
35:46The walls just lifted up, and we could feel really cold air rushing underneath.
35:52And within seconds of that, the house just blew up.
35:58I couldn't breathe. I had sucked in so much dirt that I couldn't even breathe anymore.
36:04I thought, this is it. And I remember just praying that, God, if this is it, I'm ready.
36:10On the brink of death, the fierce tornado spares Dana's life by lifting her out of the suffocating dirt.
36:18When it slams her back to the ground, she's paralyzed with fear.
36:23And I realized then that I didn't have my son.
36:25So I started screaming for him, and he came running over.
36:28And it was really, it was just a miracle of God, because we were both barefoot.
36:32He came running over to me, did not have one puncture wound on his feet.
36:37The F-5 continues towards the center of Oklahoma City, crossing major highways filled with rush hour traffic.
36:44As the tornado hurtles towards them, some people panic.
36:48They abandon their cars in a desperate attempt to find shelter.
36:51For a few, that decision has fatal consequences.
36:58Three people seeking refuge under freeway overpasses are killed by debris and the sheer force of the wind.
37:07Stranded cars block escape routes for many others.
37:11Shields Boulevard in Oklahoma City essentially became a huge parking lot.
37:16And it blocked people from being able to escape the tornado.
37:19By the time the F-5 dissipates, 40 people are dead and nearly 700 injured.
37:25My wife worked in the hospital in Norman that night.
37:31And she worked in the emergency room.
37:33And they were swamped, of course.
37:35She saw some really horrific injuries.
37:38People came in covered with splinters of wood, like pin cushions.
37:43So much wood. Awful things.
37:45Many survivors suffer multiple painful wounds from being impaled by debris.
37:50Cheryl Brown studied the injuries and deaths in Oklahoma.
37:54There were also injuries that were related to debris being embedded inside the body.
38:01All the way from small splinters to very large objects, such as two-by-fours.
38:07Many survivors suffered debris-related injuries because the tornado was so powerful.
38:12The F-5 has suffered debris-related injuries because the tornado destroyed so many homes,
38:17spewing countless shards of wood and other material into the air.
38:22The Oklahoma twister leveled nearly 3,000 houses and structures.
38:293, 2, 1, fire!
38:3473 miles an hour.
38:35Schiff and his team at Clemson University fire two-by-fours at more than 160 kilometers per hour
38:41into a variety of structures to represent the damage done during a tornado.
38:47I think that the public understands that tornadoes are very dangerous.
38:51What they don't understand is that in typical construction,
38:53they have very little protection against those types of events.
38:57When debris strikes a home, it does far more damage than simply making a hole in a wall or window.
39:03Fire!
39:05It gives the tornado a point of entry.
39:08Once inside, in-flowing air can rip apart walls and tear off the roof.
39:14The home then becomes part of the tornado's arsenal,
39:16further fueling the funnel with debris and making it even more destructive.
39:23This type of construction is very typical for a residential brick veneer in front of a wood frame wall.
39:29Fire!
39:31The missile's gone all the way through the wall cavity.
39:36Most people that have this type of house would be vulnerable to an F5 tornado.
39:40Fire!
39:45Schiff's experiments determined that for a home to withstand the deadly onslaught of debris,
39:50the brick veneer must have an eight centimeter thick backing of concrete.
39:54So this wall here would be suitable for a shelter to resist tornadoes.
40:00Most homes in Oklahoma City were brick veneer with wood frames.
40:04This common construction, coupled with the sheer number of homes in the tornado's path,
40:08increased the debris field exponentially.
40:12Dana Grimm survived with a broken back.
40:15Her son with a puncture wound to his chest.
40:18I truly believe that the reason that I was thrown twice,
40:20if I had not been picked back up and thrown again,
40:22I would have suffocated because I could not breathe in anymore.
40:25Ten supercell storms spawned 70 tornadoes that spring day,
40:29including the F5 that cut a 24 kilometer path over interstate highways
40:34and devastated several suburbs of Oklahoma City.
40:38It was sad. I think there were 14 in our own housing addition that died.
40:42And it's a miracle of God that we didn't.
40:46The Oklahoma tornado caused more than a billion dollars in damage,
40:50the costliest tornado in U.S. history.
40:54Complete and total devastation.
40:57The homes that you see over here now were completely gone.
41:01It was a rubble pile.
41:03If you had been in the open, it would not have been a very pleasant place to be.
41:09Things would have been much worse if the tornado had veered just 16 kilometers to the west,
41:14striking the heart of downtown Oklahoma City.
41:18Even so, the Moore-Oklahoma tornado and its companion twisters
41:23rank as the most deadly and destructive outbreak in modern history.
41:28They would be far surpassed by an F5 striking a major American city.
41:33That would be a mega disaster one experts warn could happen.
41:40Every year, major U.S. cities in Tornado Alley play a game of Russian roulette
41:45with massive twisters that wreak havoc there.
41:49In 1999, Oklahoma City lost the game when a giant tornado killed 40 people,
41:54injured nearly 700, and racked up costs of more than a billion dollars.
41:59Only sheer luck kept the tornado from striking downtown.
42:04Researcher Scott Ray knows the next major city to be struck by an F5 may not be so fortunate.
42:10Dallas is overdue for a large violent class tornado.
42:14Dallas, Texas is a boom town sprawled along the southern boundary of Tornado Alley.
42:20It's one of the largest and fastest growing metro areas in the U.S.,
42:24with more than 5 million residents and 600 corporate headquarters.
42:30Dallas is 10 times larger than Oklahoma City.
42:33I was shocked a bit when I saw some of the aerial footage of Oklahoma City.
42:38The amount of damage that had occurred in that was pretty amazing.
42:43Ray assists local governments with planning for hazards, especially threats from tornadoes.
42:50To help Dallas prepare for a possible mega disaster,
42:53he has modeled over 60 different scenarios
42:56of how the Dallas region would be affected by a violent tornado.
43:00For reasons of credibility, it was very important that we look at
43:03an event that actually had occurred somewhere else.
43:05So we took the event at Oklahoma City basically because the data was very good
43:10for that particular event and we could transpose it by just
43:13moving those same geographical characteristics of the tornado
43:17on top of the geography of Dallas-Fort Worth.
43:20So we got to see it kind of from our own perspective.
43:24Ray and his team painstakingly overlaid the exact path
43:28taken by the Oklahoma tornadoes over the Dallas-Fort Worth area.
43:33A mega disaster unfolds when Oklahoma's F5 tornado rampages through downtown Dallas.
43:40It would easily be the worst damaging tornado event that we have had to date in the U.S.
44:02Ray's nightmare scenario begins as a supercell storm forms over north-central Texas.
44:08A 160 km per hour tornado, an F3, touches down in a dusty field 10 miles southwest of Dallas.
44:16Its first target is the suburb of Cockrell Hill.
44:20With high packing winds in excess of 320 km per hour,
44:24cars are tossed aside, buildings are decimated.
44:28The tornado continues northeast, unrelenting in its assault on thousands of homes.
44:35The twister's internal wind speeds rise past 400 km per hour, turning it into an F5.
44:43Fueled by tons of debris, the giant tornado slows as it descends on the busy freeway.
44:50A clogged highway holds a heck of a lot more people than one that is moving.
44:54A clogged highway holds a heck of a lot more people than one that is moving comfortably.
44:58And the other problem that you have is, where do you go?
45:03Panic ensues as many abandon their cars, creating a traffic jam that traps thousands.
45:11The 443 km per hour winds effortlessly swat cars off the highway.
45:19Anyone hiding under an overpass is vulnerable to flying debris and violent winds.
45:25Cars snatched up by the powerful updraft winds are spun around inside the giant vortex,
45:31then shot out, creating a dangerous hazard for anyone in their path.
45:37Next, the deadly twister approaches downtown Dallas.
45:42Dozens of skyscrapers and tens of thousands of people crowd the city.
45:48Giant glass windows shatter, marble and bricks are ripped off buildings.
45:53A deadly shower of glass and other debris rains down onto the crowd below.
46:03Most of the skyscrapers in the Dallas-Fort Worth area are predominantly covered with glass on the outside,
46:08and that's not very durable.
46:10But the amount of damage from getting wind and broken glass spread out through a downtown area is going to be pretty dramatic.
46:17A packed commuter train snakes through the city.
46:20It's swept off the tracks and slammed into a skyscraper, killing hundreds of the train and office buildings.
46:28There's little doubt that debris would be probably the largest generator of damage in the metroplex,
46:34and it's basically because there's so much of it that can be generated, and you name it,
46:38it could be wood, bricks, gravel, just about anything you can imagine can become a projectile,
46:45and with almost unlimited supply.
46:50The tornado continues north, leaving the wreckage of downtown Dallas behind.
46:56Tornadic winds more than 500 kilometers per hour now descend on the suburban landscape of Lakewood.
47:04The 92,000 people living here have had up to 20 minutes to seek underground shelter,
47:09a seemingly reasonable chance for survival.
47:13But like the Gerald, Texas twister, those hiding in closets or bathrooms can only pray.
47:21Finally, the worst tornado in history slowly drifts skyward and dissipates.
47:26The war zone behind it is 61 kilometers long.
47:30Dallas is devastated.
47:38I don't think there's any way to really sugarcoat an event.
47:41It's going to be difficult to deal with regardless, so there's going to be a lot of damage.
47:45There are going to be a lot of people that need help.
47:47Total damages approach $5 billion.
47:50Tens of thousands are homeless and scores injured.
47:54The death toll is unknown.
47:56Fatalities are difficult to really quantitize because they involve people making decisions,
48:03and there are good decisions that can be made, bad decisions.
48:06We don't know what decision they're going to make.
48:09The best decision city planners can make is to prepare with multiple underground shelters,
48:14rehearse evacuation plans, and a vigilant public.
48:18But even that won't likely be enough.
48:23I think it would pretty much be impossible financially to build a city that could really survive
48:28violent class tornadoes or, you know, any scenario like that.
48:32With increasing populations in major metropolitan cities throughout Tornado Alley,
48:37science is in a life or death race against time to understand one of Mother Nature's biggest secrets.
48:44TORNADOES
48:48In an ideal world, we'd have radar or other instrument measurements on every tornado that occurs.
48:55In the practical world that we live in, that's just not going to happen.
48:59Okay, this storm in the next hour is going to produce this type of tornado.
49:02We're just not there yet, and it's hard to say when we'll be there.
49:06We've certainly got a ways to go.
49:09Given the limited ability to predict tornadoes, there is a very real cause for concern.
49:17Most people think about disasters as very random events that can't happen to them,
49:22and I think that holds true with tornadoes as well.
49:25If you wait long enough, something resembling the worst-case scenario is going to happen eventually.
49:33Until science learns more about these brutal forces of nature,
49:37the only thing that can be done is to prepare before a mega-disaster strikes.
50:02TORNADOES
50:32NASA Jet Propulsion Laboratory, California Institute of Technology