Tornado outbreak sequence of May 21–26, 2011
The tornado outbreak sequence of May 21–26, 2011 was one of the largest tornado outbreaks on record which affected the Midwestern and Southern regions of the United States. Most of the tornadoes developed in a corridor from Lake Superior southwest to central Texas; isolated tornadoes occurred in other areas. An especially destructive tornado destroyed one-third of Joplin, Missouri, resulting in 158 deaths and over 1,000 injuries. The Joplin tornado is the deadliest in the U.S. since April 9, 1947, when an intense tornado killed 181 in the Woodward, Oklahoma area. Tornado-related deaths also occurred in Arkansas, Kansas, Minnesota, and Oklahoma. Overall, the tornado outbreak resulted in 184 deaths, 6 of those non-tornadic, making it second only to the 2011 Super Outbreak as the deadliest since 1974, and the second costliest tornado outbreak in U.S. history behind that same April 2011 outbreak, with insured damage estimated at $4–7 billion.
Tornadoes in the United States
On May 3, 1999, a storm produced a violent tornado in the vicinity of Oklahoma City and was a part of the 1999 Oklahoma tornado outbreak, which also brought many violent storms to the states of Kansas, Arkansas, and Tennessee. In total, the storm produced 66 tornadoes over four states. The strong F5 storm took place near the town of Bridge Creek, Oklahoma, located in Grady County. During the storm, a group of students in meteorology from the University of Oklahoma had chased the storm on a Doppler on Wheels (or DOW), which scans storms while attached to a car. Doppler on Wheels data from the nearby storm revealed winds of , which was over the wind speed in the F5 classification of that time. Though the wind speed was over the F5 maximum, the tornado was not named the first ever F6 storm, as there was no F6 classification. Other scientists reviewed the DOW data taken by the students, and concluded that the estimated wind speed may have been inaccurate, but still over . Also, the wind speed recorded was taken from over above ground level. The National Weather Service also did a damage check, and found that the damage was that of an average F5 tornado.