April 2011 Tornado Information
NOAA’s preliminary estimate is that there were 362 tornadoes during the entire outbreak from 8:00 a.m. EDT April 25 to 8:00 a.m. April 28, 2011.
* During the 24-hour period from 8:00 a.m. EDT April 27 to 8:00 a.m. EDT April 28, The National Weather Service (NWS) estimates there were a total of 312 tornadoes.
* The NWS Storm Prediction Center issued severe weather outlooks five days in advance and tornado watches hours in advance.
* NWS Weather Forecast Offices issued life-saving tornado warnings, with an average lead-time of 24 minutes. NWS issued warnings for more than 90 percent of these tornadoes.
* NWS decision support for this event has been extensive. NWS Weather Forecast Offices in the affected areas of Arkansas, Tennessee, Mississippi, Alabama and Georgia advertised the potential for severe weather in the Tuesday through Wednesday timeframe since late last week. Local offices provided direct decision support services to meet the specific needs of local emergency manager partners and the general public. NWS Weather Forecast Offices issued Hazardous Weather Outlooks up to six days in advance noting the greater threat of strong, long-track tornadoes was expected.
* The largest previous number of tornadoes on record in one event occurred from April 3-4, 1974, with 148 tornadoes.
Expert analysis by NOAA Research and the National Weather Service of the fatality information indicates that at least 350 people were killed during the entire outbreak from 8:00 a.m. EDT April 25 to 8:00 a.m. April 28. There were 340 fatalities during the 24-hour-period from 8:00 a.m. April 27 to 8:00 a.m. April 28.
* The April 26-28 period had the most people killed by tornadoes in a two-day period since April 5-6, 1936, when 454 people were killed, mostly in Tupelo, Mississippi, and Gainesville, Georgia.
* April 27, 2011, is the deadliest single day for tornadoes since the March 18, 1925, tornado outbreak that had 747 fatalities across 7 states (including the Tri-State Tornado).
* The Tuscaloosa-Birmingham tornado during the April 2011 event caused at least 65 fatalities. This tornado had a maximum width of 1.5 miles and a track 80 miles long.
o These are the most fatalities from a single tornado in the United States since May 25, 1955, when 80 people were killed in a tornado in southern Kansas with 75 of those deaths in Udall, Kansas.
o The deadliest single tornado on record in the United States was the Tri-State tornado (Mo., Ill., Ind.) on March 18, 1925, when 695 died.
Ongoing (preliminary) List of Tornadoes by EF Rating (EF3 to EF5):
* EF5: 2
* EF4: 11
* EF3: 21
Note: All numbers are based on combined NOAA and historical research records and current fatality estimates. The historical research records extend back to 1680.
Month of April 2011 (and record monthly) Tornado Statistics
NWS’s preliminary estimate is that there have been more than 600 tornadoes thus far during the month of April 2011.
* The previous record number of tornadoes during the month of April was 267 tornadoes set in April 1974.
* The previous record number of tornadoes during any month was 542 tornadoes set in May 2003.
* The average number of tornadoes for the month of April during the past decade is 161.
* The overall monthly average number of tornadoes for the past decade is 106.
2011 Year-to-Date (and record annual) Statistics
NWS’s preliminary estimate is that there have been 881 tornadoes so far this year.
* The previous yearly record number of tornadoes was set in 2004 with 1,817.
* May is historically the most active month for tornadoes.
* The overall yearly average number of tornadoes for the past decade is 1,274.
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