Illinois had the most tornadoes of any state in 2023, more than tripling its number of tornadoes from the previous year, according to the National Weather Service.
With 120, Illinois ranked first in the total number of tornadoes across the U.S. last year, tying 2003 for the second largest amount of tornadoes in the state since record keeping began in 1950, said Brett Borchardt, senior meteorologist at the National Weather Service. The most tornadoes came in 2006, when Illinois saw 124 twisters, according to the NWS.
The numbers for November and December are still preliminary and may change in the next few months, Borchardt said.
The tornado season, which typically runs from April through August, got off to an early and deadly start on March 31, when 37 twisters churned through the state. Four people were killed, including a man who died when a roof collapsed at a concert venue in Belvidere, east of Rockford. On April 4, an EF-3 tornado tore through Fulton County, injuring four.
On July 12, a round of storms spawned another 13 tornadoes in the Chicago area, including two near O’Hare International Airport. There were 58 tornadoes in the NWS Chicago forecast area, which is the most reported in a calendar year.
Alabama was second with 101 tornadoes, and Texas and Colorado tied for third with 89 tornadoes, Borchardt said.
Borchardt said the high number could be due to a number of factors, including, in part, to better storm and tornado tracking technology. There were also more storm systems that produced tornadoes that moved through the Midwest, Borchardt said, and fewer in the Great Plains, leading to Illinois coming out on top.
Tornadoes are caused by a number of factors lining up, including moisture, warm air being near the surface of the Earth while cold air is aloft and certain wind conditions, said Victor Gensini, a professor at Northern Illinois University, and “we had a significant number of days where just ... all the ingredients you need for tornadoes all came together.”
The public might typically think of Tornado Alley — an area of the U.S. that includes Oklahoma, Kansas, Missouri, and parts of Louisiana, Iowa, Nebraska, northern Texas and eastern Colorado — as having the most tornadoes, but some experts say Tornado Alley is a misnomer.
“The mid-South, parts of Mississippi, Alabama, Tennessee, into southern Illinois have equal or, in some cases, greater frequency of tornadoes than in Oklahoma and Kansas,” said Illinois State Climatologist Trent Ford.
Tornado numbers also don’t account for proportionality by area, Gensini said.
“It’s a little bit deceptive when you don’t normalize by area,” Gensini said. “Because a state like Iowa is smaller than Illinois, so they automatically are going to be at a disadvantage in terms of count.”
Nonetheless, the amount of tornadoes in Illinois last year was “certainly an exception,” Gensini said. Illinois is typically expected to have 55 tornadoes per year.
In 2022, Illinois saw 39 tornadoes, after having 82 in 2021, 74 in 2020, 51 in 2019 and 60 in 2018, according to the NWS.
On a national scale, climate change certainly has an impact on the conditions that create tornadoes, such as warmer temperatures, Gensini said, but it’s harder to tell on a state level.
Some research shows there has been a slight increase in the amount of tornadoes the Midwest has seen, but due to the variability of tornadoes each year, it’s hard to say this is due to climate change, Ford said.
More research shows tornadoes occurring earlier due to climate change, Ford said. Though tornado season used to be mostly in April and June, there are a higher number of tornadoes earlier in the spring, like in March, and sometimes even in January and February, Ford said.
“We were very mild and, in some cases, actually warm in January and February, which gave us enough instability to have way above average tornado frequency in those months,” Ford said.
But this doesn’t necessarily mean Illinois will see a higher frequency of tornadoes in 2024, Ford said.
