Tornado outbreak sequence of May 2003

Preview warning: This article seems to be about a tornado outbreak. If this infobox only covers the outbreak itself, please use the |duration= parameter from the infobox header or from another 'History' box instead.
Tornado outbreak sequence of May 2003
An F4 tornado came through Moore, Oklahoma, and destroyed most of the areas affected by the 1999 Bridge Creek–Moore tornado.
Meteorological history
DurationMay 3–11, 2003
Tornado outbreak
Tornadoes363 tornadoes (62 significant)
Maximum ratingF4 tornado
Duration7 days, 22 hours
Highest windsTornadic: 207–260 mph (333–418 km/h) in Franklin, Kansas
Non-tornadic: 115 mph (185 km/h) in Wayne County, Kentucky (estimated); 105 mph (169 km/h) in Johnson County, Missouri (measured)
Overall effects
Casualties42 fatalities (+9 non-tornadic), 652 injuries (+52 non-tornadic injuries)
DamageUS$4.1 billion (US$5.8 billion 2019 CPI)
Areas affectedGreat Plains, Eastern United States

From May 3 to May 11, 2003, a prolonged and destructive series of tornado outbreaks affected much of the Great Plains and Eastern United States. Most of the severe activity was concentrated between May 4 and May 10, which saw more tornadoes than any other week-long span in recorded history; 335 tornadoes occurred during this period, concentrated in the Ozarks and central Mississippi River Valley. Additional tornadoes were produced by the same storm systems from May 3 to May 11, producing 363 tornadoes overall, of which 62 were significant. Six of the tornadoes were rated F4, and of these four occurred on May 4, the most prolific day of the tornado outbreak sequence; these were the outbreak's strongest tornadoes. Damage caused by the severe weather and associated flooding amounted to US$4.1 billion (US$5.8 billion in 2016), making it the costliest U.S. tornado outbreak of the 2000s. A total of 50 deaths and 713 injuries were caused by the severe weather, with a majority caused by tornadoes; the deadliest tornado was an F4 that struck Madison and Henderson counties in Tennessee, killing 11. In 2023, tornado expert Thomas P. Grazulis created the outbreak intensity score (OIS) as a way to rank various tornado outbreaks. The tornado outbreak sequence of May 2003 received an OIS of 232, making it the fifth worst tornado outbreak in recorded history.