1999 Oklahoma tornado outbreak
 | This article needs additional citations for verification. (March 2008) |
 | |
| Duration | ~72 hours |
|---|---|
| Tornadoes confirmed | 66 |
| Max. rating1 | F5 tornado |
| Fatalities | 48 |
| Damage | $1.9 billion (2007 USD) |
| Areas affected | Oklahoma, Kansas, Texas, Tennessee |
| 1Most severe tornado damage; see Fujita scale | |
The 1999 Oklahoma tornado outbreak was a severe weather event that lasted from May 3 until May 6, 1999 and brought violent storms to Oklahoma, Kansas, Arkansas, and Tennessee. This article concentrates on the events on May 3, when 66 tornadoes broke out in Oklahoma and Kansas. The most significant tornado first touched down southwest of Chickasha, Oklahoma, and became an F5 before dissipating over Midwest City, Oklahoma. The tornado tore through Bridge Creek, Oklahoma and Moore, Oklahoma, causing $1.1 billion in damage. Forty-eight people perished during the outbreak. This tornadic event ranks in severity with the Palm Sunday tornado outbreak of 1965. With a total of 66 tornadoes, it was the most prolific tornado outbreak in Oklahoma history, although not the deadliest.
Outbreak description
May 3, 1999 started sunny, warm, and humid across the affected region. The Storm Prediction Center in Norman, Oklahoma initially issued a "slight risk" for severe weather for most of the state of Oklahoma early that morning. By late morning the latest observations and forecasts began to indicate an increasing likelihood of widespread severe weather, and the SPC upgraded sections of the southern plains to "moderate risk." By 3 p.m. it had become evident that a widespread severe weather event was imminent. Parts of Oklahoma and Kansas were then further upgraded to "high risk". When a "high risk" is issued, this usually indicates the potential for a significant severe weather event, including damaging tornadoes. The SPC issued a tornado watch by mid-afternoon as conditions gathered together for what would be a historic tornado outbreak. By the afternoon the CAPE values reached nearly 6,000 J/kg over the region. Large supercell thunderstorms developed and in the late afternoon through the mid-evening hours of that Monday, tornadoes began to break out across the state.
Confirmed tornadoes
| FU | F0 | F1 | F2 | F3 | F4 | F5 | Total |
|---|---|---|---|---|---|---|---|
| 0 | 33 | 12 | 10 | 7 | 3 | 1 | 66 |
(based on NOAA Storm Data)
The Moore F5
Path
The most significant tornado of the outbreak touched down just southwest of the community of Amber, Oklahoma, and headed northeast, parallel to Interstate 44, just after another tornado had passed over the airport in Chickasha, OK. (Note: it may be argued that the storms touching down in Chickasha and Amber were the same storm; however, for weather tracking purposes, each touchdown is counted as a separate tornado which is most probable.) The storm continued moving northeast, destroying the community of Bridge Creek and crossing I-44 just north of Newcastle.
The tornado then crossed the Canadian River, passing into far southern Oklahoma City. As it passed over Bridge Creek, Oklahoma, around 6:54 p.m., a Doppler On Wheels (DOW: Wurman et al. 1997, Wurman 2001) mobile Doppler weather radar detected winds of 301 mph (484 km/h), +/- 20 mph inside the tornado at a height of 32 m AGL (Wurman et al. 2007)[1] (The old record was a 257-268 mph wind measurement from a Doppler weather radar near Red Rock, Oklahoma, as reported in a formal publication by Bluestein et al. (1993)). These winds, however, occurred above the ground, and winds at the surface may not have been quite this intense. The tornado continued on into Moore and then passed over the intersection of Shields Boulevard and Interstate 35 and back into Oklahoma City, crossing Interstate 240 near Bryant Avenue. The storm then turned more northerly, striking parts of Del City and Tinker Air Force Base near Sooner Road as an F4 before diminishing over Midwest City and finally lifting near the intersection of Reno Avenue and Woodcrest Drive.
Casualties
Thirty six people were killed in this tornado. More than 10,500 buildings and 47 businesses were destroyed. This tornado caused $1.1 billion in damage, making it the costliest single tornado in U.S. history, adjusted for inflation.[2] This was the deadliest tornado since the April 10, 1979 Wichita Falls, Texas Tornado which killed 42 people.[3] However, early warning saved many lives. Warnings were issued well in advance of the tornado's arrival, and the Oklahoma City broadcast media interrupted programming to follow the storms on radar and even by helicopter. The death toll likely would have been higher if people had not been warned so far in advance. Following the storm, three of the local television stations in Oklahoma City: KOCO-TV, KWTV and KFOR-TV continued coverage of the damaging and deadly tornadoes through May 4.
Impact
| State | Total | County | County total |
|---|---|---|---|
| Kansas | 6 | Sedgwick | 6 |
| Oklahoma | 40 | Cleveland | 11 |
| Grady | 12 | ||
| Kingfisher | 1 | ||
| Logan | 1 | ||
| McClain | 1 | ||
| Payne | 1 | ||
| Pottawatomie | 1 | ||
| Oklahoma | 12 | ||
| Tennessee | 3 | Perry | 3 |
| Texas | 1 | Titus | 1 |
| Totals | 50 | ||
| All deaths were tornado-related | |||
The risk of using overpasses as storm shelters
Three of the deaths reported in the tornado were from people who took shelter underneath overpasses in the area of the path of the Moore-Bridge Creek F5 tornado. The deaths occurred at the 16th Street overpass over Interstate 44 in Newcastle (just east of Bridge Creek), at the Shields Boulevard overpass over Interstate 35 in Moore, and the overpass at mile marker 176.5 on Interstate 35 in rural northwestern Payne County, west of Stillwater.
The two overpass deaths associated with the Oklahoma City storm occurred when the tornado was at peak intensity. However, the tornado that caused the fatality at Interstate 35 mile marker 176.5 in Payne County was in F2 intensity when it struck the overpass and was NOT in an urban area. This suggests, contrary to the Kansas Turnpike video (see the El Dorado Lake Tornado), that a tornado need not be a large, violent tornado with a considerable debris cloud to cause fatal injuries to people seeking shelter from storms under overpasses. In addition to the fatal injuries to three people, there were also many severe, potentially life-threatening injuries inflicted upon people underneath the overpasses that in some cases has left them with permanent disabilities.
Fujita scale
This tornado's remarkable wind speed (at the high extreme of the Fujita Scale's F5) led to much speculation that the scale would be modified to include an F6 category, due to the winds possibly exceeding 320 mph (515 km/h). This speculation ignored the fact that the Fujita scale measures damage rather than windspeed, since the scale was developed prior to the introduction of Doppler weather radar. Windspeed estimates associated with the different categories represent the speeds scientists believe are required to produce that damage rather than the windspeed in that particular storm. The damage caused by an F5-designated tornado leaves very little room for a higher category.
The tornado was the last official F5 to hit the United States with the old Fujita scale rating. The next category 5 tornado occurred on May 4, 2007 in Greensburg, Kansas during the May 2007 Tornado Outbreak and killed 11 people. Since February 1, 2007 the National Weather Service has used the Enhanced Fujita Scale to rate tornadoes, and the Greensburg tornado was recorded as the first EF5 tornado. This tornado however, is not the last category 5 tornado to be rated on the fujita scale, as Canada still uses the Fujita scale, and a tornado that occurred in Manitoba in 2007 was rated an F5.
Other significant tornadoes
In addition to the devastating F5 tornado that hit the southern suburbs of Oklahoma City, there were numerous other significant tornadoes in the outbreak. An F3 tornado hit the town of Stroud (in between Oklahoma City and Tulsa) on Interstate 44, destroying the Tanger Outlet Mall. The mall has not been rebuilt.
Another F4 hit the town of Mulhall, north of Guthrie, destroying most of the town and even toppling the city's water tower. This wedge tornado was very wide, at times exceeding width of over a mile (1.6 km). According to storm chaser Roger Edwards, it may have been as violent if not even more than the F5 Moore/Bridge Creek tornado.[4] A Doppler On Wheels (DOW) mobile radar observed this tornado as it crossed Mulhall. The DOW documented the largest ever observed core flow circulation with a distance of 1600 m between peak velocities on either side of the tornado, and a roughly 7 km width of peak wind gusts exceeding 43 m/s, making the Mulhall tornado the largest tornado ever measured quantitatively[5]. The DOW measured a complex multiple vortex structure[6] with several multiple vortices containing winds of up to 115 m/s rotating around the tornado. The 3D structure of the tornado has been analyzed in Lee and Wurman 2005[7].
One of the final tornadoes in the outbreak almost hit the studios of ABC affiliate KTUL-TV in Tulsa, located on Lookout Mountain, a few miles west of the city itself, in the early morning hours of May 4 around 12:15 a.m. CDT. Then chief meteorologist Travis Meyer advised his co-workers to take shelter while still on the air reporting on the approaching tornado. It weakened before reaching the station.
The May 3 tornado event was part of a 3-day event that included tornadoes in Kansas and Texas. A deadly tornado killed six people in Haysville and Wichita, Kansas, the same day. The event killed 1 person in Texas on Tuesday, May 4 and then killed four in Tennessee on Wednesday and Thursday.
Damage estimates
Note: The following was adapted from public domain, official National Weather Service web sites.
The following is a list of the number of homes and businesses damaged by the tornadoes in the outbreak:
| Oklahoma and Cleveland Counties | Other Counties |
|---|---|
| Homes destroyed: 1,780. | Homes destroyed: 534. |
| Homes damaged: 6,550. | Homes damaged: 878. |
| Businesses destroyed: 85. | * Businesses destroyed: 79. |
| Businesses damaged: 42. | Businesses damaged: 54. |
| Churches destroyed: 3. | Churches destroyed: 2. |
| Schools destroyed: 2. Public buildings destroyed: 4. |
Public buildings damaged: 7. |
| Apartments destroyed: 473. | Apartments damaged: 568. |
- Includes 53 stores at the Tanger Outlet Center in Stroud.
Source: National Weather Service Norman, OK Forecast Office--
See also
- List of North American tornadoes and tornado outbreaks
- Climate of Oklahoma City
- Nowhere to Run! - Storm Stories episode
References
- ^ Doppler On Wheels - Center for Severe Weather Research (cswr.org)
- ^ However, adjustment for growth in wealth shows the 27 May 1896 Saint Louis–East Saint Louis tornado to be the costliest on record. See Brooks, Harold E. (2001). "Normalized Damage from Major Tornadoes in the United States: 1890–1999". Weather and Forecasting. 16 (1): 168–176. doi:10.1175/1520-0434(2001)016<0168:NDFMTI>2.0.CO;2.
{{cite journal}}: Cite has empty unknown parameter:|month=(help); Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Brooks, Harold E. (2002). "Deaths in the 3 May 1999 Oklahoma City Tornado from a Historical Perspective". Weather and Forecasting. 17 (3): 354–361. doi:10.1175/1520-0434(2002)017<0354:DITMOC>2.0.CO;2.
{{cite journal}}: Cite has empty unknown parameter:|month=(help); Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Central Oklahoma Tornado Intercept: 3 May 1999 (Roger Edwards)
- ^ Wurman, Joshua (Jan 2007). "Low-Level Winds in Tornadoes and Potential Catastrophic Tornado Impacts in Urban Areas". Bulletin of the American Meteorological Society. 88 (1). American Meteorological Society: 31–46. doi:10.1175/BAMS-88-1-31.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Wurman, Joshua (Jun 2002). "The Multiple-Vortex Structure of a Tornado". Weather and Forecasting. 17 (3). American Meteorological Society: 473–505. doi:10.1175/1520-0434(2002)017<0473:TMVSOA>2.0.CO;2.
{{cite journal}}: CS1 maint: date and year (link) - ^ Lee, Wen-Chau (Jul 2005). "Diagnosed Three-Dimensional Axisymmetric Structure of the Mulhall Tornado on 3 May 1999". Journal of the Atmospheric Sciences. 62 (7). American Meteorological Society: 2373–93. doi:10.1175/JAS3489.1.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help)
External links
- May 3, 1999 tornado activity overlaid on a Google Map Tornado History Project
- The Great Plains Tornado Outbreak of May 3, 1999 (National Weather Service, Norman, Oklahoma)
- The 3 May 1999 Oklahoma Tornadoes (David Schultz, CIMMS)
- Google Maps' location of Stroud, Oklahoma, with the bulldozed lot of the former Tanger Outlet Mall in the upper left of the screen, just north of Interstate 44
- May 3 Oklahoma Tornado Special video section from KOCO-TV