Views of the 1999 Bridge Creek F5 Tornado and the World Record DOW Velocity

Aerial view of damage left behind by the Bridge Creek tornado. The tornado’s proximity to the I-44 gave the Doppler On Wheels an excellent opportunity to analyze the storm at close range for an extended period of time.

□ On May 3rd, 1999, all the atmospheric ingredients needed for the creation of large, long-tracked tornadoes came together over the Great Plains. A dry line atop the Oklahoma and Texas Panhandles separated a mass of warm, humid air from dry, cool air slowly encroaching from the west. Weather balloons released across Tornado Alley rose into the air in erratic zigzags, and indication of rapidly shifting winds at different altitudes. The atmosphere was unstable, and by late morning the National Weather Service had upgraded the severe weather risk from slight to moderate.

Around 4pm, weather satellites captured a series of supercell thunderstorms exploding out of the afternoon sky. At 6:20pm, a large funnel descended from the sky near Amber, Oklahoma. The tornado, later dubbed “A9” on survey maps, rapidly intensified as it thundered northeast through Grady County. Within minutes of touchdown, the storm expanded into a massive wedge more than a half mile wide. Storm chasers captured the tornado as it tore past the Chickasha Municipal Airport and entered an unpopulated area to the northeast.

The mesocyclone that spawned the tornado was exceptionally violent. Low hanging clouds or “skud” swirled around the massive tornado at terrific speeds as large satellite vortices rotated around the main funnel, causing additional damage. Local news stations in Oklahoma City quickly focused their attention on the Grady County storm, and regular programming was interrupted by live broadcasts of the approaching tornado.

The tornado struck little for many miles before taking aim on the small, unincorporated town of Bridge Creek. By the time the tornado reached the town’s first cul-de-sacs it had expanded to a mile in width.

View of F5 damage on County Street 2977 in Bridge Creek. The highest concentration of fatalities throughout the tornado’s path occurred in this area, and 75% of them were related to mobile homes.

The tornado was at peak intensity as it approached the I-44 Interchange in Bridge Creek. Unfortunately, many of the households in the area were mobile homes with no underground storm shelters. Some residents sought protection in irrigation ditches and culverts beneath roads, though many were seriously injured by the blizzard of flying debris. One young couple was caught outside while running a short distance to their neighbor’s storm cave (Pam, Brown, Kruger et al., 2001). Their bodies were found wrapped in debris more than 200 yards from their destroyed home.

Damage in the Bridge Creek area was among the most intense ever surveyed. Frame homes were swept completely away and mobile homes in the direct path of the storm disappeared without a trace. Aerial imagery around the I-44 Interchange showed a 200-yard wide core of extreme damage in which vegetation was ripped from the ground and trees were stripped of all bark and branches. Surveyors also documented vehicles thrown up to one mile. In total, 12 people were killed in Bridge Creek. The fatality to injury ratio was seven times higher in Grady County than in the Oklahoma City suburbs, a testament to the storm’s incredible ferocity in the area.

Aerial view of F5 damage in Bridge Creek. One survivor in this area crawled deep into a narrow drainage pipe as the tornado approached from the southwest. He was injured by flying debris and nearly ripped out of from his unconventional hiding space as the storm passed over. (Image by Doug Crowley)

The remains of a frame home in Bridge Creek (the DOC Service Assessment stated this home was in Cleveland County near Moore). Three of the 12 fatalities in Grady County were in frame homes, many of which were swept cleanly away. The vegetation scouring was among the most intense ever surveyed.

Perhaps the most infamous image of the May 3rd outbreak is this picture of a pulverized pick-up truck wrapped around a telephone pole in Grady County. Unlike many other tornadoes that have entered populated areas, there were no fatalities in vehicles during the Bridge Creek tornado. (Image by Curtis Carey)

This well-anchored home in Grady County was struck by the tornado at maximum intensity. Grass was ripped from the ground and low lying vegetation was stripped completely of bark and branches, both indications of extremely intense surface winds. (Image by Jim LaDue)

The Bridge Creek tornado traveled parallel to the I-44 for much of its life. Had the tornado travelled a half mile farther to the south, it would have spent over 20 miles directly over the freeway and likely killed dozens of motorists. Surprisingly, none of the tornado’s fatalities occurred in vehicles. There were four fatalities, however, in which people attempting to flee were killed while running to their vehicles. Additionally, there were two well-documented deaths beneath freeway overpasses. A third overpass death often attributed to the tornado was actually caused by a separate storm north of Oklahoma City near the town of Mulhall.

It is remarkable that only two women were killed seeking shelter beneath overpasses. Both locations were struck by the tornado after it had reached peak intensity, likely allowing more than two dozen others to escape with their lives – though many of the survivors were left with serious injuries. In the image above, a mangled vehicle was found beneath an (unoccupied) overpass after being blown more than half a mile.

The path of the tornado along the I-44 gave the Doppler On Wheels (DOW) an excellent opportunity to stay within close proximity to the tornado for a long period of time. As a result, the DOW was able to thoroughly analyze the storm throughout its mature stage. It is a common misconception that mobile doppler radar “measures” tornadic winds and provides researchers with a single numerical value. Instead, mobile radar analyzes the movement of condensation and debris and calculates a statistical range in which the particle velocity can be estimated.

As the Bridge Creek tornado passed the I-4 interchange, the DOW calculated a velocity that likely fell between 281 and 321mph. The figure, often quoted as 301mph +-20mph, remains the highest radar velocity ever recorded. This is by no means, however, evidence to support that the Bridge Creek tornado was “the strongest tornado ever recorded.” Far less than 1% of all violent tornadoes have been tracked by mobile radar, and of the tornadoes that have been analyzed, only a fraction of their total path lengths were recorded. The Bridge Creek tornado’s unique path adjacent to a freeway gave researchers a rare opportunity, and it is not surprising that the record velocity was calculated given the near perfect circumstances.

Image of the Bridge Creek tornado from the DOW. The time stamp indicates that this picture was taken around the time the record reading was calculated. (cswr.org)

Ground scouring indicates that the tornado remained intense as it entered McClain County. The path width narrowed slightly, and the tornado’s appearance changed into a ‘stovepipe’ formation with a wide debris cloud at its base. After remaining parallel to the I-44 for more than 40 minutes, the tornado reached a bend in the freeway and crossed over it, leading to McClain County’s only fatality. A woman who had taken shelter under an overpass with her son was swept away and killed while others who had taken shelter in the same location were injured by flying debris and found plastered in red dirt.

Vegetation scouring near the Grady/McClain County line. (Image by Doug Crowley)

Three views of the F5 tornado. The first two images show the tornado as it entered Cleveland County. While the tornado often appeared as a massive wedge, the width of the primary damage path through Moore was generally less than 200 yards wide. At right, the appearance of the tornado after it had entered Moore and filled with debris.

The city of Moore was nearly motionless as the tornado entered Cleveland County. Sirens had been sounding for nearly an hour, and on-air meteorologists had advised viewers in the strongest language ever broadcast to seek shelter or “you will not survive this storm.” Entire rows of tightly packed homes were obliterated as the tornado entered town from the southwest, filling the sky with debris. One of the first housing subdivisions directly impacted by the tornado was Eastlake Estates, located to the south of Westmore High School. While the tornado engulfed a wide area, the extreme damage was confined to a streak 100 yards wide in the center of the damage swath.

Aerial view of Eastlake Estates, where the last instances of F5 damage were documented.. (Image by Bob Webster)

Another view of Eastlake Estates. The F5 damage was confined to two clusters of homes. Approximately four homes experienced F5 damage on 131st Terrace (the first row of destroyed homes at top right). Just a block to the northeast on 129th Street, another three homes were swept away in F5 fashion. The close proximity of the homes made determining the exact F-Scale contours difficult. At extreme top right is the Country Place subdivision, where F5 damage also occurred. (Image by Bob Webster)

National Weather Service employees photographed the row of homes that were swept away in F5 fashion in Eastlake Estates. At right, completely debarked trees in a field to the west of Moore.

Near F5 damage in Moore. Heavy vehicles showered down onto neighborhoods outside the corridor of extreme damage (Grazulis, 2001). (Image by Bob Webster)

Pronounced ground scouring marked the tornado’s path through an undeveloped area east of Moore. The tornado made a curve to the north and entered Del City at F4 intensity. (Image by Bob Webster)

The tornado swept through a trucking facility on the I-240, killing two employees. Ground scouring was significant, and damage in the area was “near F5” in intensity. (Image by Bob Webster)

Rows of homes in Midwest City were reduced to piles of rubble as the tornado entered Oklahoma County. (Image by Bob Webster)

Aerial view of high-end F4 damage near Sooner Avenue in Midwest City. The tornado remained intense throughout its entire life and continued causing F4 damage until moments before dissipating. (Bob Webster)

Eleven people were killed in Moore, and a further 12 were killed in Oklahoma County, specifically in Del City and Midwest City. A detailed morbidity report concluded that a third of the documented victims were killed in “recommended places”, meaning in an interior room in a frame home. Excluding the deaths in Grady and McClain County, it is probable that most of the victims in the Oklahoma City area had taken appropriate shelter. The intensity of the tornado made survival, even in some well-built homes, difficult. At least two of the fatalities in Moore occurred when vehicles were hurled atop people huddled in their homes.

The tornado was the deadliest in the United States during the 1990’s and remained the single most damaging tornado in history until 2011. Even so, the death toll of 36 people was surprisingly low. Excellent warning, live television broadcasts, good visibility and the tornado’s fairly slow forward speed reduced the number of fatalities. Had the tornado formed two hours later, after dark, the death toll could have easily been twice as high.

The path of the F5 tornado is still visible years later in satellite images. A trail of deforestation can be seen at bottom left near Bridge Creek, and the northerly turn the tornado made in Del City is visible at top right.

Some falsely believed that the Bridge Creek tornado was ‘proof’ that no single tornado could ever again cause over 100 fatalities. This assumption was shown to be terribly wrong in 2011 when an EF5 tornado killed 158 people in Joplin, Missouri. While the Bridge Creek tornado’s death toll was testament to improved forecasting and technology, the storm was, in a sense, perfect from a forecasting perspective. Tornadoes that intensify rapidly near populated areas and tornadoes obscured by precipitation will continue to pose a major threat to cities across the county. A tornado causing over 1,000 fatalities in United States is not just a possibility but, given enough time, a meteorological certainty.

*Bob Webster’s complete aerial photo gallery of tornado damage in Moore and Oklahoma County can be found here. Used with permission.

The List of the Strongest Tornadoes Ever Recorded: Part II

During the 2008 Super Tuesday outbreak, one of the longest tracked tornadoes in history ripped through primarily rural forestland in central Arkansas. Near the small community of Zion, the tornado hurled a Hummer a quarter mile from an obliterated residence. Another vehicle in the same area was mangled beyond recognition and wrapped around a denuded tree. The tornado does not appear on the

During the 2008 Super Tuesday outbreak, one of the longest tracked tornadoes in history ripped through primarily rural forestland in central Arkansas. Near the small community of Zion, the tornado hurled a Hummer a quarter mile from an obliterated residence. Another vehicle in the same area was mangled beyond recognition and wrapped around a denuded tree. Whether the tornado was capable of causing EF5 damage will never be known since the storm, like most, reached peak intensity in unpopulated areas. (Images by wxmandan)

□ For a tornado to be considered for categorization, it must have caused at least one fatality, and it must have occurred after the conception of the Fujita Scale in 1970. Damage intensity and, to a lesser extent, wind duration are the only variables considered, without regard to total path length, width or monetary loss. Information has only been taken from damage photographs or reliable survey reports, not unverified statements or accounts. While far from definitive, this list is the result of literally hundreds of hours of research, e-mails across the country and conversations with other storm chasers. I believe it is as accurate a list as is available. It is flexible and always open to change.

The indefinitive list of the strongest tornadoes:

1. Jarrell, Texas – May 27, 1997

2. Smithville, Mississippi – April 27, 2011

3. Kemper County (Philadelphia), Mississippi – April 27, 2011 

4. Bridge Creek, Oklahoma – May 3, 1999    

5. Bakersfield Valley, Texas – June 1, 1990 

6. Phil Campbell, Alabama – April 27, 2011

7. El Reno, Oklahoma – May 24th, 2011

8. Smithfield, Alabama – April 4, 1977    

9. Brandenburg, Kentucky – April 3, 1974 

10. Andover, Kansas – April 26, 1991

11. New Hartford (Parkersburg), Iowa – May 25, 2008

12. Joplin, Missouri – May 22, 2011

13. Guin, Alabama – April 3, 1974 

14. Moore, Oklahoma – May 20, 2013

15. Mulhall, Oklahoma – May 3, 1999

16. Wheatland, Pennsylvania – May 31, 1985

17. Rainsville, Alabama – April 27, 2011

18. Barneveld, Wisconsin – June 8, 1984

19. Will County (Plainfield), Illinois – August 28, 1990

20. Xenia, Ohio – April 3, 1974

Various images of tornado damage, with relative intensity increasing from left to right. At left, the 2011 Phil Campbell tornado left most trees partially debarked and stripped of branches. The ground also shows high velocity impact marks but no obvious scouring of grass (Image by John Phillips). At center left, impact marks and partial ground scouring in after the 2011 Smithville tornado. At center right, the near complete debarking of all foliage in Smithville (Images by C. Welch). At right, completely obliterated vegetation and severe ground scouring following the 2011 El Reno tornado. (Image by Jim LaDue).

Various images of tornado damage with relative intensity increasing from left to right. At left, the 2011 Phil Campbell tornado left most trees partially debarked and stripped of branches. The ground also shows high velocity impact marks but no obvious grass scouring (Image by John Phillips). At center left, impact marks and partial ground scouring after the 2011 Smithville tornado. At center right, the near complete debarking of all foliage in Smithville (Images by C. Welch). At right, completely obliterated vegetation and severe ground scouring following the 2011 El Reno tornado. (Image by Jim LaDue).

10. Andover, Kansas – April 26, 1991

From the steps of the Terradyne Country Club, Earl Evans captured the exact moment the F5 tornado entered the Golden Spur mobile home park. Just southwest of the park, large homes (similar to the ones in the foreground) were swept cleanly away.

□ One of the most well-known tornadoes in United States history touched down near Clearwater, Kansas, at the height of a severe weather outbreak on April 26th, 1991. Storm chasers filmed the tornado as it slowly gained strength and took aim on the southern suburbs of Wichita. After ripping through homes in Hayesville, the “elephant trunk” funnel steered towards McConnell Air Force Base, where thousands of post-Gulf War military personnel and their families were being housed. As the tornado entered the southern edge of the base, the power failed and the sirens across the area fell silent. The tornado filled with debris and entered a period of rapid intensification as it crossed the southern edge of the base’s runway. Four people were killed in a residential area east of the base, all of them caught out in the open while running for shelter (Grazulis, 2001).

After exiting Wichita, the tornado reached F5 intensity and expanded to a quarter mile in width. The small town of Andover, which hugs the Kansas Turnpike ten miles east of downtown Wichita, was impacted directly by the tornado at maximum intensity. Large, two-story homes to the east of 159th Street were swept completely away as the tornado approached the Golden Spur mobile home park. Most of the community’s residents were sheltering in a large, underground storm cave when the tornado obliterated the park, but some people failed to make it to shelter on time. More than 80% of the mobile homes in the park were turned to splinters by the F5 tornado and 11 people were killed. Adjacent to the park, a couple and their teenage son stopped their car and sought shelter in a ditch along Andover Road. The man and his son were killed in the unforgivable blizzard of debris from hundreds of disintegrating mobile homes, and the woman was seriously injured (Grazulis, 2001). Aerial damage surveys later documented a trail of empty foundations and scoured grass through the housing developments of Andover. Ground crews photographed mobile home frames wrapped around completely debarked trees in the Golden Spur community.

Video of the Andover tornado shows some of the most violent tornadic rotation ever filmed. Even so, there may have been an even stronger tornado during the outbreak.The longest tracked tornado on April 26th, 1991, roared through the unpopulated Oklahoma countryside and was undoubtably capable of producing F5 damage. The “Red Rock” tornado caused no fatalities, however, so was not considered for the “strongest” list.

Damage from the Andover tornado in the vicinity of the Golden Spur mobile home park (at right). Grass scouring is clearly visible in the swath of extreme damage. As the tornado crossed Andover Road, it left perhaps the most impressive instance of wind rowing ever photographed. The debris originated from a subdivision of large homes that was obliterated. (Image by Fernando Salazar)

Surveyors photographed a vehicle that had been carried almost a mile from the Golden Spur mobile home park. It was so thoroughly mangled that they were unable to determine whether it was a truck or a car. (Grazulis, 1993)

Several views of F5 damage in the vicinity of Chapel Drive, where large two-story homes were swept completely away.[

Several views of F5 damage in the vicinity of Chapel Drive, where large two-story homes were swept completely away.[

The remains of two large, well-built homes that were swept away in F5 fashion near 143rd Street. Circular ground scouring is visible in the lefthand image. Despite the severity of the damage, there were no fatalities in frame homes. Extensive warning and clear visibility gave residents more than 30 minutes to seek shelter underground. Also, the area was much less developed in 1991 than it is today. (Image from TVCII)

9. Brandenburg, Kentucky – April 3, 1974

Before and after views of Brandenburg. Perched on the corner of the ridge overlooking the Ohio River was “one of the nicest modern houses in Brandenburg” (visible in the before image at right center). The home was swept completely away in the tornado, killing the occupants. Green Street (the third street from the edge of the bluff) was the location of more than half of the tornado’s fatalities. (Meade County Heritage)

□ During the 1974 Super Outbreak, a tornado of incredible ferocity touched down in the hills of Northern Kentucky, a region unaccustomed to violent tornadoes. The storm intensified as it passed through unpopulated areas north of Hardinsburg, and began causing F5 damage as it approached the Indiana border. Several well-constructed homes were swept completely away along Highway 1239 as the violent tornado turned to the northeast at 50mph. Witness statements suggest that the tornado took on a “stovepipe” appearance and was fairly difficult to distinguish from the rain falling around it.

Few people were aware of the danger in Brandenburg, a small community on the Ohio River. A local disc jockey on the edge of town saw the tornado approaching and sent out a frantic last-minute warning to the residents of Meade County. For many of those not listening to their radios, the first warning was the roar of the tornado. One survivor later said that she “heard a noise that sounded like the world was coming to an end.” The fast-moving tornado ripped through the tiny town in less than 30 seconds. The worst damage occurred to homes on a bluff just west of Brandenburg’s business district. The nine homes that lined Green Street were obliterated, leading to 18 fatalities (Meade County Heritage). Several large, well-built two-story homes were left as bare concrete slabs, including a recently constructed home where four people were killed. One body was blown several hundred yards and found near the banks of the Ohio River at the base of the bluff. Additionally, trees were debarked and sheared just above ground level, and a news photographer documented extensive grass scouring just west of town (Macy, 1974).

Over the years, some of the more infamous tornadoes during the ’74 Super Outbreak have acquired almost mythical status. Damage photographs and first-hand reports, however, suggest that the lesser known Brandenburg tornado was perhaps the most powerful of the outbreak.

Just west of Brandenburg, a home was swept completely away, leaving nothing but an empty basement plastered in mud. The fatality rate in Brandenburg was the highest of any town affected during the 1974 Super Outbreak. A total of 27 residents were killed in the town of Brandenburg, where basements are commonplace. By contrast, 20 deaths occurred in the town of Guin, Alabama, which had a slightly larger population at the time. Additionally, the Guin tornado moved in excess of 70mph and impacted the town after dark, two variables that dramatically increase the likelihood of fatalities. (Data collected by Scott Koerner)

Two views of severe damage southwest of Brandenburg. At left, the collapsed basement walls of a home that was swept away. At right, view of mangled cars that were thrown long distances into a field that was partially scoured of grass. (Images by Donald Macy)

Close view of the

Close view of the “modern house” that was swept away above Main Street, resulting in two fatalities. Low-lying shrubbery was stripped bare, an indication of extreme surface winds. (NWS Louisville)

8. Smithfield, Alabama – April 4, 1977

Aerial view of F5 damage to large homes on Belmont Lane. The powerful tornado skirted just north of the highly populated core of Birmingham.

□ Birmingham, Alabama, was struck by an exceptionally violent tornado during a stormy spring day in 1977. Like most deadly tornadoes in the South, the Smithfield tornado was fast moving and difficult to see behind a curtain of heavy rain. The storm touched down west of downtown Birmingham and rapidly strengthened as it sped to the northeast. Four died, including a mother and her two children, as the tornado ripped through Smithfield Estates, a small neighborhood just east of North Pratt. Homes in the area were swept completely away and at least one vehicle were thrown more than 200 yards.

The tornado intensified further as it ripped through a forested area and approached Smithfield Manor, an upper middle class street lined with large two-story homes. Some victims in the neighborhood had heeded warnings and taken shelter in basements but others were caught unexpectedly by the F5 tornado. There were multiple fatalities in several families as an entire row of homes on Belmont Lane was obliterated, leaving nothing but clean foundations and empty basements. Photographic evidence indicates that the tornado scoured patches of grass from the ground and stripped trees bare of bark and branches. In total, 22 people were killed by the tornado, and more than 100 homes were completely destroyed. The death toll was remarkably low considering the severity of the building damage, which was some of the most intense ever photographed at the time.

Prof. Fujita, who was in Alabama at the time, gave the tornado an F5 rating. One piece of NWS literature reports that Fujita “toyed with the idea of rating the Smithfield tornado an F6.” Decades later, the 2011 Tuscaloosa/Birmingham tornado passed directly over some of the exact same areas affected by the 1977 event, causing damage to the same properties.

Extreme damage from the Smithfield tornado. At left, the sharp boundary between F5 damage and homes with only minor damage is evident. Most of the well-built homes destroyed in the tornado had basements, likely reducing the death toll. The body of one victim was reportedly carried over half a mile.

The remains of a brick home in Smithfield. Pine trees in the background have been reduced to featureless trunks.

7. El Reno, Oklahoma – May 25, 2011

View of the EF5 tornado minutes after touchdown. The tornado spent approximately 100 minutes on the ground and travelled nearly 70 miles, an exceptional distance for the Great Plains. (Image from JeopardyTempest / Youtube)

□ Twelve years after the Bridge Creek event, a tornado of equal ferocity passed within 20 miles of downtown Oklahoma City. The monster storm was tracked by rapid scanning mobile doppler radar as it touched down near the I-40 and rapidly intensified. Researchers recorded a doppler velocity of 280mph moments before the rain-wrapped tornado fell out of range and plowed to the northeast. As of this writing, the figure has yet to be officially released. Vegetation was ripped from the ground in the EF5 damage swath, and the few trees left standing were completely stripped of bark and branches. Three fatalities occurred in two vehicles as the tornado crossed the I-40. The victims’ bodies were left “unrecognizable” and discovered stripped of clothing a quarter mile from the freeway (AP, 2011). Rescue crews were unable to determine if the victims had exited their vehicles and attempted to take shelter on the ground.  The two cars were mangled so severely that only pieces of their frames were recovered. Additionally, an oil field adjacent to the I-40 was impacted directly by the EF5 tornado, resulting in the movement of a 1.9 million pound drilling derrick (Ortega, 2011). Reporters documented an oil tanker weighing in excess of 20,000lbs that was thrown a mile from the production site (KFOR, 2011). Aerial imagery revealed no visible ground impacts, so the tanker may have travelled the entire distance in one toss.

After passing to the north of El Reno, the tornado barreled eastward through the rural outskirts of Oklahoma City. A small cluster of homes near the town of Piedmont was directly impacted by the storm. Approximately a dozen homes were completely obliterated, and several residents were killed. More than a dozen large vehicles from the neighborhood were hurled several hundred yards into a field that was partially scoured of vegetation. The tornado continued to the east-northeast for an additional 35 miles but failed to impact any populated areas. Most of the damage and all of the fatalities occurred in the first 30 miles of the damage track.

A mesonet station near El Reno recorded a wind gust of 151mph in the outer fringes of the tornado’s circulation. The wind gust, which falls in the EF3 range, provides some indication that the Enhanced Fujita Scale grossly underestimates wind speeds in violent tornadoes. Ground scouring in the El Reno tornado was similar to the Bridge Creek tornado, and its path length was significantly longer. The Bridge Creek tornado paralleled the I-44 and was closely followed by radar for much of its life. The El Reno tornado was analyzed only briefly as it crossed the I-40, so higher winds may have occurred.

The remains of car hurled a half mile in Piedmont. Vegetation and vehicle damage of this severity are indicators of incredible intensity. (Image by Jim LaDue)

Severe vehicle damage and grass scouring near a neighborhood in Piedmont, where several fatalities occurred. (Image by Rebecca Manney)

Aerial views of the oil tanker that was thrown a mile from a production site on the other side of the I-40. Several other tankers were hurled long distances, and machinery in excess of 1 million pounds was moved.

Aerial views of an oil tanker that was thrown a mile from a production site on the other side of the I-40. Several other tankers were hurled long distances, and machinery in excess of 1 million pounds was moved.

View of severe ground scouring southwest of Piedmont.

On the same day as the El Reno tornado, two other tornadoes were likely capable of causing EF5 damage. One tornado in Chickasha scoured grass from the ground, swept away atleast one well-built home and ripped pavement from roads (at left). Nearby, a tornado in Goldsby left several large homes as bare foundations and caused pronounced grass scouring (at right).

On the same day as the El Reno event, two other violent tornadoes developed south of Oklahoma City. One tornado in Chickasha scoured grass from the ground, swept away atleast one well-built home and ripped pavement from roads (visible at left). Nearby, a tornado in Goldsby left several large homes as bare foundations and caused pronounced grass scouring (at right). Both tornadoes were likely capable of causing EF5 damage and may deserve a place on the “strongest” list.

6. Hackleburg/Phil Campbell, Alabama – April 27, 2011

View of the catastrophic tornado near the town of Phil Campbell. The storm maintained peak intensity for an exceptionally long period of time - the swath of EF5 damage was longer than the entire track of all the other EF5 tornadoes on April 27, 2011. (Video still by lookalika maan)

View of the catastrophic tornado near the town of Phil Campbell. The storm maintained peak intensity for an exceptionally long period of time – the swath of EF5 damage was longer than the entire track of all the other EF5 tornadoes on April 27, 2011. (Video link)

□ One of the most notable tornadoes in modern history touched down in a forested area near the town of Detroit, Alabama. After spending 15 minutes tearing through sparsely populated sections of Marion County, the fast moving storm ripped through the tiny town of Hackleburg at EF5 intensity, causing 18 fatalities. Buildings across most of the town were damaged, but the worst destruction was confined to a streak only 200 yards wide. In the worst affected areas, trees were completely debarked, well-constructed homes were swept from their foundations and a large manufacturing plant was reduced to a pile of twisted metal (NWS, 2011).

The tornado’s intensity remained remarkably uniform as it exited town and sped to the northeast at more than 70mph. Five minutes later, the storm reached the town of Phil Campbell, a small community with just over 1,000 residents. The town’s population was well-warned of the approaching storm, but interior rooms provided no protection from the exceptionally violent tornado. Twenty six people were killed in Phil Campbell, including four members of one family. Photographic evidence indicates the tornado scoured grass from exposed hillsides, and surveyors documented a large section of pavement that was peeled from a street on the eastern edge of town. Additionally, aerial imagery suggests that the roof of an underground storm cellar was ripped from the ground near Highway 237.

A post-storm damage survey by the NWS indicated that the most intense damage occurred in the unincorporated community of Oak Grove, about eight miles northeast of Phil Campbell. As the tornado roared through the area, a large, two-story brick home of excellent construction was swept completely away. The bodies of the home’s two occupants were found far from the empty foundation in a field to the east. Surveyors later determined that the EF0 damage contour reached a peak width in excess of one mile in Oak Grove, but the path of extreme damage remained narrow throughout the tornado’s life. In total, the storm travelled 132 miles – one of the longest officially measured damage paths in history. Surveyors documented EF5 and “near EF5” damage from Hackleburg to Tanner, a distance of nearly 70 miles. Despite hitting mostly unpopulated forestland and tiny towns, the tornado killed 72 people, most of whom were killed in a 25 mile swath between Hackleburg and Mount Hope.

The Phil Campbell tornado was one of the most impressive tornadic events of the past century. The storm’s intensity, rapid forward pace, huge size and exceptional path length have led many to consider it the “strongest tornado ever recorded.” Winds in the storm may have easily exceeded the Bridge Creek and El Reno events, but the storm’s fast movement reduced the duration of the most intense winds to less than five seconds. As a result, the tornado caused less pronounced ground and vegetation scouring than some other, slower-moving EF5 storms. A post dedicated specifically to this tornado can be found here.

Hackleburg was the first town directly impacted by the fast moving EF5 tornado. As the tornado entered town, a large church and several homes were reduced to empty concrete slabs. The few remaining bushes and trees in the inner damage swath were stripped bare and left clinging to the ground by only a few roots. High winds within the tornado’s large circulation affected all of the buildings visible in this photograph, including the green-roofed church at extreme upper left, which was destroyed. (Image from HBTV)

Three images of extreme damage in Hackleburg. At top left, view of large trees that were completely debarked near the Wrangler Factory (Image by Patrick Flanagan). At top right, a vehicle that was rendered unrecognizable in the vicinity of Clay Street (Image by John Phillips). At bottom, the tornado was powerful enough to scour concrete from the ground (Image by Niccolò Ubalducci). Considering the speed of the tornado and the width of the EF4 and EF5 damage contour, the most extreme destruction likely occurred in less than five seconds.

At left, extreme vegetation damage and possible ground scouring along a hillside on Pinion Drive in Phil Campbell. At right, a storm cellar 200 yards to the southwest of the left image appears to have lost its ground-level roof in the storm (Image by HGTV). The Hackleburg/Phil Campbell tornado caused some of the most violent wind damage ever documented.

At left, extreme vegetation damage and possible ground scouring on Pinion Drive in Phil Campbell (Image by Robin Conn). At right, a storm cellar (center) at the edge of Phil Campbell appeared to have lost its ground-level roof in the storm (Image from HBTV). Due to its strength and longevity, the Hackleburg/Phil Campbell tornado likely had the most destructive potential of any tornado in recent history.

Damaged grass marks the path of EF5 damage near County Road 81, one mile east of Phil Campbell. In the foreground, large trees that have been debarked and sheared just above ground level are visible. A few hundred yards to the east, a cluster of empty foundations is all that remains of several frame homes along Cornelius Drive, one of which was large and very well-constructed. Three people died in two of the obliterated homes, and a dozen vehicles were thrown more than 150 yards. Just beyond the small lake at top, another three people were killed in the complete destruction of two homes at the edge of a wooded area. (Image from HBTV)

__________

Certain damage indicators are unique to EF5 tornadoes. These include:

1. Pronounced ground and vegetation scouring (perhaps the best indicator of extreme intensity).

2. Completely debarked trees.

3. Well-constructed buildings swept from their foundations.

4. Vehicle’s thrown great distances and mangled beyond recognition.

5. Granulation of debris.

6. Incredible phenomena (eg. an 800lb safe thrown 200 yards in Rainsville, AL) and wind rowing.

7. High above-ground fatality rates in frame homes.

For reasons unknown, some intense tornadoes do not leave behind all seven damage indicators. Ground scouring, while strongly correlated with wind speed, occurs readily in some tornadoes and not others.

Damage in Oak Grove following the 2011 Phil Campbell tornado. Researchers at the NWS believed the tornado reached peak intensity in this area, and at far right a large, two-story brick home of excellent construction was swept completely away. There is no grass scouring near the home, however, whereas the 1999 Bridge Creek tornado scoured grass while at F4 intensity.

__________ Click to see:

Part I

Part III

Part IV