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Tornado outbreak of May 4–6, 2007

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Tornado outbreak of May 4–6, 2007
Satellite perspective of the tornadic supercells over the Great Plains on the evening of May 5
TypeExtratropical cyclone
Tornado outbreak
DurationMay 4–6, 2007
Tornadoes confirmed129 confirmed
Max rating1EF5 tornado
Duration of tornado outbreak256 hours, 9 minutes
Damage$268 million[1]
Casualties14 fatalities, 89 injuries
Areas affectedGreat Plains, Central United States
1Most severe tornado damage; see Enhanced Fujita scale2Time from first tornado to last tornado

The tornado outbreak of May 4–6, 2007 was a major and damaging tornado outbreak that significantly affected portions of the Central United States. The most destructive tornado in the outbreak occurred on the evening of May 4 in western Kansas, where about 95% of the city of Greensburg in Kiowa County was destroyed by an EF5 tornado, the first of such intensity since the 1999 Bridge Creek–Moore tornado.[2][3] The supercell killed 13 people, including 11 in Greensburg and two from separate tornadoes.[4][5][6][7] At least 60 people were injured in Greensburg alone. It was the strongest tornado of an outbreak which included several other tornadoes reported across Oklahoma, Colorado, Kansas and South Dakota that occurred on the same night.[8]

Although the most damaging tornado of the outbreak sequence occurred in Greensburg on the 4th, twenty-five tornadoes were confirmed that day.[9] That number exploded to 84 the following day (May 5), with many tornadoes near the affected area from the previous night.[9] Most were in open country, but there were injuries in at least two spots in Kansas, and one death reported near a county lake in Ottawa County.[9] 14 more tornadoes were confirmed on May 6th in the region before the outbreak finally ended.[9]

Meteorological synopsis[edit]

The 1300 UTC day one convective outlook, showing a high risk area in south-central Nebraska and western Kansas, surrounded by a large area of moderate and slight risk across the Great Plains.

It is the combination of warm humid air from the Gulf and dry air from the deserts of the Southwest that produce deadly storms.[10] These conditions create an unstable severe storm creating arena.[10] Although tornadoes occur on every continent except Antarctica they are especially common in North America, specifically the United States.[10]

This severe weather outbreak can be traced back to a powerful, slow-moving low pressure area with a warm front to the north over Nebraska and Missouri.[11] On May 4, the low stalled over the High Plains and additional moisture coming from the Gulf of Mexico moved in behind the warm front and increased amounts of instability across much of the region, with CAPE values as high as 5,500 J/kg.[12] In addition, the dry line, which marks a divided line between the dry and humid air mass, was positioned over the southern High Plains. This allowed for the initiation of scattered supercells on May 4. High wind shear also allowed for intense rotation in the atmosphere. All the ingredients were present for the developing of supercell thunderstorms producing damaging wind, large hail and tornadoes.[13]

The Storm Prediction Center issued a moderate risk for severe weather across western Kansas and small portions of Oklahoma, Colorado and Nebraska for May 4, while temperatures were in the mid to high 80s°F (near 30 °C). The atmosphere remained capped for much of the day, but storms began to develop in the late afternoon hours in western Oklahoma and the eastern Texas Panhandle.[13] The most intense supercells developed in the early evening hours across northwestern Oklahoma and southwestern Kansas. They eventually produced 25 tornadoes, including the devastating Greensburg tornado and three other extremely large tornadoes which followed the Greensburg tornado late that evening.[14] The supercells remained intact well into the overnight hours as the extremely unstable air mass precluded rapid dissipation expected with the loss of daytime heating which would normally be expected in the Plains. The last tornado of the night did not lift until shortly after 2:00 a.m. early on May 5.[13]

On May 5, the SPC issued a high risk of severe weather for Central Kansas and central Nebraska, while moderate and slight risks for severe weather extended for areas far beyond.[15] The low pressure system in place moved northward, but the extending front had barely moved.[16] The storms were quick to develop. Severe weather reports were already coming in by late morning, and the first tornado reports came in during the early afternoon hours.[17] The most intense activity took place during the late afternoon and evening hours as supercells developed along a long line from South Dakota to North Texas. Over 80 tornadoes were confirmed that day, along with hail as large as softballs and straight–line winds as strong as 90 mph (145 km/h).[17] The activity weakened in the late evening, but not before the last tornadoes were reported in Iowa in the overnight hours.

The low gradually weakened and became less conducive for severe weather development on May 6. Nonetheless, the SPC issued a moderate risk for severe storms over parts of central Kansas and northern Oklahoma as the trough remained in place.[18] The activity was far less than on the two previous days, however there were still several additional tornadoes across the Plains (all of them weak, mostly EF0).[19] The system finally left the area on May 7 and did not produce any more significant severe weather.[20]

Confirmed tornadoes[edit]

Confirmed tornadoes by Enhanced Fujita rating
EFU EF0 EF1 EF2 EF3 EF4 EF5 Total
0 66 42 15 5 0 1 129

The Greensburg tornado family[edit]

Storm history and damage[edit]
The NOAA Weather Radio audio of a tornado warning issued for Greensburg, Kansas on May 4, 2007.
Doppler wind velocities on NWS weather radar shortly before the tornado hit Greensburg. A second developing circulation (mesocyclone), which later developed into another very large tornado, is also evident.

The storm that would produce the EF5 Greensburg tornado began forming after 5:00 pm CDT (2200 UTC) in the northeastern corner of the Texas Panhandle, and went through phases in the early evening across the Oklahoma Panhandle with a few isolated tornadoes.[21] It slowly organized itself as it moved northeast through portions of Oklahoma, and then into Kansas.[12] The first tornado warning with this cell was issued at 8:35 pm CDT (0135 UTC) for Clark County, Kansas,[22] and the tornado first touched down at about 9:00 pm CDT (0200 UTC). Several storm chasers captured the formation of a tornado southwest of Greensburg around 9:20 pm CDT (0220 UTC).[23]

The tornado apparently strengthened as it neared Greensburg and began moving due-north towards the town, and at 9:38 pm CDT (0238 UTC), storm chasers reported that it had grown to over 1/2 mile in diameter. Trees were snapped and oil tanks were destroyed in this rural area, with oil strewn across pastures and roads.[24][25] Several satellite tornadoes were observed as the very large wedge approached the city of Greensburg from the south. At 9:41 pm CDT (0241 UTC) the National Weather Service office in Dodge City issued a Tornado emergency for Greensburg. A tornado emergency is an unofficial product used only for extremely life–threatening situations when a large and likely violent tornado is on the ground and approaching a populated area.[26][27]

The center of Greensburg, Kansas, twelve days after being hit by the 2007 tornado.

The massive tornado continued north, following Main Street into the south side of Greensburg. Many homes (including an entire row of seven adjacent residences) were swept completely away in this area just south of town, three of which were well-bolted to their foundations. Damage in this area was rated EF5 as a result.[28] The tornado weakened slightly as it entered residential areas in southern Greensburg, but remained violent as numerous homes were destroyed or leveled. Continuing north, downtown Greensburg was completely devastated by the tornado, with numerous businesses destroyed. Two schools, a tractor supply company, the Greensburg City Hall and other businesses fell victim to the violent winds and were destroyed or flattened. A motel on the west side of town was severely damaged, trees throughout the town were completely denuded and debarked, and vehicles were thrown hundreds of feet. The city's water tower was completely toppled and smashed, and the visitor's center at the Big Well (which is the world's largest hand-dug well) was completely destroyed. Train cars were also overturned and hazardous materials teams were called to inspect the wreckage. A tank car carrying about 14,000 gallons (53,000 liters) of ammonia started to leak when workers lifted it. The courthouse and the grain elevator were spared the worst of the tornado's effects. Meanwhile, the Greensburg meteorite, which was feared to have been blown away, was found and recovered a few days afterwards. Greensburg High School was mostly destroyed by the tornado, sustaining EF4 damage.[28] Numerous homes were swept away across from the high school, four of which were well-bolted to their foundations, warranting an EF5 rating at those residences. The Kiowa County Memorial Hospital was severely damaged at EF3 intensity, and a 4.9-ton reinforced concrete beam was lifted from the structure and thrown onto a nearby vehicle.[28][29][30] Past downtown, neighborhoods in northern Greensburg were flattened before the tornado left the city limits. The tornado continued north of Greensburg, executing a loop in a farm field before dissipating. The total path length was 22 miles (35 km), and the width of the funnel reached 1.7 miles (2.7 km). Overall, 95% of Greensburg was destroyed. A total of 961 homes and businesses were destroyed, 216 received major damage and 307 received minor damage.[31][32]

The destroyed Greensburg High School after the tornado.

After the main Greensburg tornado dissipated, another large wedge tornado developed north of town. This enormous EF3 tornado rapidly grew to about 2 miles (3.2 km) in diameter as it moved northeast. Near the beginning of the path, two farms were destroyed at high-end EF3 strength, a combine was tossed 1/4 of a mile and smashed to pieces, farm machinery and irrigation pivots were destroyed, along with trees and power lines. The tornado crossed into Edwards County, where additional farms were destroyed, one person was injured, and livestock was killed before the tornado dissipated south of Belpre.[33][34][35] A third large EF3 wedge tornado developed north of Haviland, initially causing minor tree and irrigation pivot damage in Kiowa and Edwards Counties as it moved northeast. In Pratt County, this third tornado grew to over a mile wide, killing one person and injuring another as a farmhouse was swept away. Crossing into Stafford County, the tornado destroyed additional farms, killed livestock, and injured another person. One home in this area was swept completely away, and a vehicle was thrown 3/4 of a mile and mangled beyond recognition. The tornado then weakened and dissipated south of Macksville.[36] Southeast of Macksville, yet another large EF3 wedge tornado developed and moved northeast. A police cruiser was thrown 1/4 of a mile from a road by the tornado and destroyed, killing the officer inside who was watching the previous tornado as it dissipated. Over a dozen farms, trees, pieces of farm machinery, vehicles, irrigation pivots, and power poles were damaged or destroyed by this fourth and final large wedge tornado before it dissipated.[37]

After additional surveys, NWS Dodge City had confirmed 12 tornado tracks by the Greensburg supercell in Kansas alone on May 4, including several weaker and satellite tornadoes that occurred along with the four large wedge tornadoes.[34] The new Enhanced Fujita Scale was implemented on February 1, 2007, and the Greensburg tornado was the first tornado to be rated EF5 on it. Including tornadoes from the older Fujita Scale, the most recent F5 to hit the United States had been on May 3, 1999 during the 1999 Oklahoma tornado outbreak, when the 1999 Bridge Creek–Moore tornado affected parts of Central Oklahoma.[34]

This tornado event surpassed the number of fatalities registered on May 4, 2003 during the May 2003 tornado outbreak sequence when eight people were killed by three separate tornadoes that affected areas around Kansas City and points south and west of the city; the last major deadly outbreak registered in Kansas prior to the Greensburg event.[38] It was also the deadliest day and single tornado to hit the state of Kansas since an F5 tornado (which was also the last F5 in that state before this event), hit Wichita and Andover in Sedgwick and Butler counties, killing 17 during the Andover, Kansas Tornado Outbreak on April 26, 1991.[39][40] The Greensburg event was also the deadliest single tornado in the United States since a tornado hit Volusia County in central Florida on February 2, 2007 where 13 were killed in an EF3 tornado. It was also the deadliest day for tornadoes since 20 people were killed in six communities on March 1, 2007.


Marine One, carrying George W. Bush, flies over the devastated community of Greensburg, Kansas Wednesday, May 9, 2007.

Hours after the tornado hit, Greensburg was judged unsafe and was fully evacuated. Some of the injured were transferred to hospitals in Dodge City and Wichita. The Kansas National Guard was called in to assist in the security measures. Over 100 Red Cross officials were called in while some worked with the Federal Emergency Management Agency for the recovery efforts. Shelters were established at the Haviland High School and Barclay College in nearby Haviland, Kansas and the Oddfellow Lodge in Macksville, Kansas.[41] After the tornado, looting was reported in the community and at least seven suspects, including four soldiers that were not part of the relief effort and went to Greensburg on their own, were arrested and faced charges of burglary and theft.[42][43] A dusk-to-dawn curfew was put in place in the community after the tornado hit.[44]

The American Red Cross maintained a list of "Safe and Well" families at their website [45] Meanwhile, officials also set up a shelter for lost and injured animals as they reported to have found 163 animals alive in Greensburg after the tornado.[46] Kansas Governor Kathleen Sebelius and President George W. Bush both declared Kiowa County a disaster area.[47]

Total damage from the outbreak was estimated at about $268 million,[1] and insured damage from the Greensburg tornado alone was estimated at $153 million.[48]

Non-tornadic events[edit]

Rain amounts during the first week of May in the Missouri River Basin

In addition to the tornadoes, widespread flooding occurred across central North America as a result of the same system producing continuous thunderstorms. There were two major reasons for the flooding: The storm system itself moved very slowly, having produced significant tornado outbreaks in almost the same places for three days. In addition, the storms moved along each other's paths, so one storm dropped heavy rains on the same place that the storm before it did (this is also known as "training").

Flooding on the 102 River at Maryville, Missouri. The river is normally about the size of a creek and is on the extreme right of the photo

Across portions of eastern Nebraska and western Iowa, rainfall amounts exceeded locally 6 inches (152 mm).[49] In northeastern and central Kansas, rainfall amounts approached 5 – 6 inches locally (125 – 150 mm).[50][51] In North Dakota,[52] southern Manitoba and southern Saskatchewan, heavy rainfalls of 1 – 3 inches (25 – 75 mm) fell from this system from May 4 to May 7.[53] Similar amounts were reported in Alberta on May 3 and May 4.[54]

Some of the worst flooding affected Topeka, Kansas, where several rescues had to be made, and the Kansas City Metro Area, where several roads were closed. In neighboring Missouri, levees broke along the Missouri River which caused extensive flooding to hundreds of homes and the northwest and central part of the state. The National Guard were assisting on filling sandbags to protect homes, schools and plants across the state which experienced some of the worst flooding since the Great Flood of 1993 which affected most of the Mississippi River Valley. Torrential rains on May 10 had also caused flooding in parts of southern Missouri as well as in eastern Kansas.[55][56] The heavy rains also affected activities surrounding the Riverfest (Wichita River Festival) which postponed some events until May 14.[57] The Arkansas River reached record levels near Haven when it crested at 13.08 feet on May 8. Some flooding into low-lying areas was also observed in the Wichita Metropolitan Area. Rainfall amounts in southern and southeastern Kansas also exceeded 6 inches (152 mm) over a two-day period on May 6 and May 7. There were several reports of farmers who lost several cattle who have been toss by the high water levels.[58]

In Aberdeen, South Dakota, 7.75 inches (197 mm) of rain fell the evening of May 5 into the early morning hours of May 6, causing significant flooding in some areas around the city. It was also the city's new 24‑hour record rainfall, breaking the old mark of 5.20 inches (132 mm) set in June 1978.[59] The highest unofficial rainfall total was reported in Epiphany, South Dakota where as much as 10 inches (254 mm) fell during the weekend.[60] The highest official report of rain, 8.73 inches (222 mm) at Columbia, South Dakota, set a new official 24–hour May rainfall record for the entire state of South Dakota.[61]

In southern Oklahoma City and surrounding communities, strong straightline winds caused damage to several buildings and downed trees and power lines in the early morning hours of May 7, with cleanup efforts being complicated due to flooding rains accompanying the storm. About 11,000 homes were without power during the event.[62] There were also reports of floods across many other areas in Oklahoma. Oklahoma Governor Brad Henry had declared a state of emergency for all 77 counties across the state due to all the severe weather including the tornadoes, the flash floods and hail.[63]

Snow was also reported across higher elevations in Colorado, Wyoming, Nebraska and Utah with local amounts of up to one foot (30 cm) across central Colorado.[64]

See also[edit]


  1. ^ a b National Climatic Data Center. "NCDC Storm Events-Select State". Storm Events Database. National Oceanic and Atmospheric Administration. Archived from the original on May 9, 2009. Retrieved March 2, 2010.
  2. ^ "At Least 10 Dead After Supercell Tornado Demolishes Kansas Town". May 5, 2007. Retrieved May 5, 2007.
  3. ^ KAKE-TV. "Greensburg Tornado Rated at EF-5". Archived from the original on May 9, 2007. Retrieved May 6, 2007.
  4. ^ KAKE-TV. "Police Officer Injured In Tornado Dies". Archived from the original on September 28, 2007. Retrieved May 9, 2007.
  5. ^ "Death toll rises to nine after tornado destroys Kansas town". The Clarion-Ledger. Retrieved May 6, 2007.[dead link]
  6. ^ "Deadly twister flattens Kansas town". CNN. Archived from the original on May 10, 2007. Retrieved May 5, 2007.
  7. ^ CNN, Storm-hit Kansas residents return home[permanent dead link] 6:30 am EDT, May 8, 2007, retrieved 7:50 am EDT, May 8, 2007.
  8. ^ "SPC Storm Reports for 5/4/07". Storm Prediction Center. May 4, 2007. Retrieved May 5, 2007.
  9. ^ a b c d "One Year after Tornado, Greensburg Still Struggling to Survive". Insurance Journal. Retrieved April 2, 2016.
  10. ^ a b c "How Kansas Tornado Became a Monster". Retrieved April 2, 2016.
  11. ^ US Department of Commerce. "Daily Weather Maps, Saturday May 5, 2007". Retrieved May 14, 2007.
  12. ^ a b Davies, Jon. "CAPE/CIN (J/Kg, Saturday May 5, 2007)". Archived from the original on June 5, 2007. Retrieved May 14, 2007.
  13. ^ a b c Davies, Jon. "The Greensburg Tornado Environment on 4 May 2007". Archived from the original on May 16, 2007. Retrieved May 14, 2007.
  14. ^ NOAA, National Weather Service. "Tornado Watch 227". Retrieved May 14, 2007.
  15. ^ Storm Prediction Center. "May 5, 2007 1300 UTC Day 1 Convective Outlook". Retrieved May 14, 2007.
  16. ^ US Department of Commerce. "Daily Weather Maps, Sunday May 6, 2007". Retrieved May 14, 2007.
  17. ^ a b "SPC Storm Reports for 5/5/07". Storm Prediction Center. May 5, 2007. Retrieved May 5, 2007.
  18. ^ Storm Prediction Center. "May 6, 2007 1300 UTC Day 1 Convective Outlook". Retrieved May 14, 2007.
  19. ^ "SPC Storm Reports for 5/6/07". Storm Prediction Center. May 6, 2007. Retrieved May 7, 2007.
  20. ^ "SPC Storm Reports for 5/7/07". Storm Prediction Center. May 7, 2007. Retrieved May 8, 2007.
  21. ^ National Climatic Data Center. "Event Record Details: (04/1721)". National Weather Service. Retrieved February 29, 2008.
  22. ^ "KDDC [050139] - Tornado Warning". Archived from the original on July 15, 2014. Retrieved February 29, 2008.
  23. ^ "KDDC [050220] - Tornado Warning". Retrieved February 29, 2008.[dead link]
  24. ^
  25. ^ Robb Lawson. "Barton and Ellsworth County Tornado". National Weather Service. Retrieved May 5, 2007.
  26. ^ Herb White. "Aware: Climate, Water, Weather" (PDF). National Weather Service. Archived from the original (PDF) on April 11, 2008. Retrieved February 29, 2008.
  27. ^ CNN. "Survivors sought as more storms threaten Plains". Archived from the original on May 9, 2007. Retrieved May 6, 2007.
  28. ^ a b c Marshall, Tim (2007). "Damage Survey of the Greensburg, KS tornado" (PDF). American Meteorological Society. Retrieved July 9, 2014.
  29. ^ McCarthy, Daniel (2007). "The Greensburg, KS Tornado" (PDF). American Meteorological Society. Retrieved July 9, 2014.
  30. ^ KAKE-TV. "Greensburg Meteorite Recovered". Archived from the original on September 28, 2007. Retrieved May 9, 2007.
  31. ^
  32. ^ "Search Resumes in Devastated Kansas Town". Archived from the original on May 10, 2007. Retrieved May 5, 2007.
  33. ^
  34. ^ a b c NWS Dodge City. "Greensburg Tornado Rated EF-5 (updated May 22)". Retrieved May 22, 2007.
  35. ^ National Climatic Data Center. "NCDC Storm Reports". National Weather Service. Archived from the original on May 9, 2009. Retrieved February 29, 2008.
  36. ^
  37. ^
  38. ^ "Tornadoes of the Past". The Tornado Project. 2003. Archived from the original on April 28, 2007. Retrieved May 5, 2007.
  39. ^ "Sedgwick County Tornado Details". National Climatic Data Center. April 26, 1991. Retrieved May 5, 2007.
  40. ^ "Butler County Tornado Details". National Climatic Data Center. April 26, 1991. Retrieved May 5, 2007.
  41. ^ "Greensburg Suffers Significant Damage In Tornado". Archived from the original on May 8, 2007. Retrieved May 4, 2007.
  42. ^ KAKE-TV. "Soldiers Accused of Looting in Court". Archived from the original on September 28, 2007. Retrieved May 10, 2007.
  43. ^ "Looting suspects arrested in storm-ravaged Kansas town". Archived from the original on May 17, 2007. Retrieved May 8, 2007.
  44. ^ Probst, Jason (May 7, 2007). "Officials to tour area today; dusk-to-dawn curfew in place". The Hutchinson News. Archived from the original on May 9, 2007.
  45. ^ "Red Cross Safe and Well Website". Archived from the original on November 30, 2006. Retrieved May 4, 2007.
  46. ^ KAKE-TV. "Animals Are Tornado Victims Too". Archived from the original on September 28, 2007. Retrieved May 9, 2007.
  47. ^ KAKE-TV. "President Bush Declares Disaster in Kansas". Archived from the original on June 13, 2007. Retrieved May 6, 2007.
  48. ^ | 06/21/2007 | Insured losses from twister: $153 million Archived September 30, 2007, at the Wayback Machine
  49. ^ NWS Omaha, Nebraska. "24 Hour Rainfall Reports Received the Morning of Sunday May 6th, 2007". Archived from the original on June 20, 2007. Retrieved May 7, 2007.
  50. ^ NWS Topeka, Kansas. "24 hour precipitation ending around 7 AM May 6, 2007". Retrieved May 7, 2007.
  51. ^ NWS Wichita, Kansas. "Weekend of Severe Weather For Central Kansas!". Retrieved May 7, 2007.
  52. ^ NWS Bismarck, North Dakota. "Precipitation Totals - May 4–7, 2007". Retrieved May 7, 2007.
  53. ^ "Public Weather Warnings for Canada". Environment Canada. May 5, 2007. Archived from the original on May 5, 2007. Retrieved May 5, 2007.
  54. ^ "Special Weather Statements for Alberta". Environment Canada. May 5, 2007. Archived from the original on September 9, 2007. Retrieved May 5, 2007.
  55. ^ "Missouri flooding keeps sandbaggers busy". Archived from the original on May 18, 2007. Retrieved May 11, 2007.
  57. ^ KAKE-TV. "Riverfest Deals With Rising Water". Archived from the original on September 28, 2007. Retrieved May 11, 2007.
  58. ^ NWS Wichita. "Record and near Record Flooding the 2nd week of May". Retrieved May 14, 2007.
  59. ^ NWS Aberdeen, South Dakota. "Record Rainfall". Retrieved May 7, 2007.
  60. ^ NWS Sioux Falls, South Dakota. "Storm Total Rainfall Reports for the Weekend". Retrieved May 7, 2007.
  61. ^ McGahee, Alvin (June 1, 2007). "Selected U.S. City and State Extremes May 2007". NCDC. Retrieved February 5, 2008.
  62. ^ "Rain causes flooding; bridge collapse; power outages".
  63. ^ KOCO-TV. "State Of Emergency Declared For All 77 Counties". Retrieved May 8, 2007.
  64. ^ NWS Denver, Colorado. "NE Colorado Snow Event Recap May 5–7, 2007". Retrieved May 7, 2007.

External links[edit]

Coordinates: 37°36′16″N 99°17′37″W / 37.604316°N 99.293488°W / 37.604316; -99.293488