Illinois ranks in the top 10 for most tornadoes per square mile in the nation. According to the National Weather Service on average 49 confirmed tornadoes touchdown in the Land of Lincoln and 1300 across the United States, during a calendar year.
Last year 69 tornadoes were confirmed with 2 fatalities, injuring 27 people, while causing 50 million dollars in damage. Tornadoes can happen any month of the year with the peak months of April, May and June. May has the highest number of tornadoes with 534 confirmed touchdowns since 1950, while June follows in second with 508 and April at 505. In 1919 and 1933 no tornadoes were reported, while in 2006 124 were confirmed. The peak hours for tornadoes is from 2 PM until 8 PM with the peak hour being 6 PM.
The National Weather Service in Lincoln says central Illinois has 12 of the top 20 counties in Illinois for most tornadoes per square mile:
- #2 Logan
- #4 Sangamon
- #5 McLean
- #11 Macon
- #12 Champaign
- #13 Piatt
- #16 Douglas
- #18 Vermilion
- #20 Coles
According the Illinois Emergency Management Agency 78% of all tornadoes in Illinois have been weak, meaning winds of less than 110 mph. Strong tornadoes packing winds of 110 to 167 mph account for 20 percent of all tornadoes. Only about 2% of tornadoes have been violent, EF4 or EF5, with the latest coming on April, 9 2015 as the powerful storm moved from north of Rochelle to the Village of Fairdale.
The largest outbreak in the state was on April, 19th 1996 when 39 tornadoes tore across Illinois with 4 EF3s. Illinois State Climatologist Jim Angel says Illinois has experienced two of the worst tornadoes in the nation's history: the infamous Tri-State tornado of March 18, 1925, with 695 dead, 2000 injured, and $130 million in property damage; the Mattoon tornado of May 26, 1917, with 101 dead, 638 injured, and $55 million in property damage.
The National Weather Service office in Lincoln says since 2008 78% of severe weather events have had advanced warning with an average lead time of 16 minutes. Lead time is very important, as that time increases it will allow you to get to a safe place ahead of the storm. It's important that we are prepared for severe weather year round as severe storms can strike at anytime of the year, just not in the Spring.