The May 3, 1999, Oklahoma Tornado Outbreak was the first stage of a severe weather event that lasted from May 3 until May 6 and brought violent storms to Oklahoma, Kansas, Arkansas, and Tennessee. This article concentrates on the events in Oklahoma. On May 3, 1999, 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. The Moore F5 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 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) (The old record was a 257-268 mph wind measurement from a Doppler 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. This was the deadliest tornado since the April 10, 1979 Wichita Falls, Texas Tornado which killed 42 people. 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.
