Tornadoes in Illinois are nothing new. The storms that swept through northern Illinois this week showed how quickly tornadoes can pop up from intense thunderstorms and quick swings in temperature.

In 2023, Illinois topped other states with the dubious distinction of most confirmed tornadoes in the nation.

“Illinois is not No. 1 in many things, but in 2023, we were No. 1 for something we would probably not want to be No. 1 for,” said Duane Friend, a state master naturalist and climate change specialist with the University of Illinois Extension.

In 2023, Illinois had the highest number in the nation with 120 confirmed tornadoes.

The only year that topped it was 2006, when there were 124 confirmed twisters.

In past years, Texas often held the No. 1 spot for tornadoes, as it lies in what is considered the country’s Tornado Alley.

However, throughout most of 2023, Illinois was outpacing most states, Friend said.

Speaking as part of the Extension Wilderness Wednesday programs earlier this year, which are co-sponsored by the University of Illinois Extension and the Kankakee River Valley Forest Preserve District, Friend discussed the evolving and changing nature of tornado patterns in Illinois and across the U.S. in an online presentation.

“Illinois had at least one tornado in every month in 2023 with the exception of September, November and December,” Friend said.

This marks only the seventh time since records have been kept that the state of Illinois experienced tornadoes in at least nine months of the year.

Additionally, Friend said, “We had a lot of tornadoes in early January, and even more in March, and a bunch in July.”

March 31, 2023, had the single-day record of tornadoes in Illinois with 37.

Climatologists have taken out observational bias – including more people in Illinois and additional tornado detection systems – and the frequency of tornadoes in Illinois still are increasing since 1950, Friend said.

The first-ever radar-detected tornado was recorded at the University of Illinois back in 1953.

“The good news is that the majority of these are the weaker tornadoes,” he said. “Still, these can cause limb damage [or] roof damage, so they are still not to be taken lightly.”

Predicting shifting patterns

Today, research groups at both the University of Illinois at Urbana-Champaign and Northern Illinois University are hard at work investigating tornadoes, Friend said.

Experts still can’t predict the exact date, time and location of future tornadoes, he said, but by looking at persisting weather conditions, especially those that last longer than three days, researchers have some accuracy in predicting a “pretty good chance of a tornado outbreak.”

Tornadoes can occur in the late afternoon after the daytime heating, the rising of air and more instability, which causes more thunderstorms.

A study conducted by Northern Illinois University found that Tornado Alley, which includes East Texas, Oklahoma, Kansas, Nebraska and the Dakotas, still is the No. 1 region in terms of tornado activity, Friend said.

The geography of the Gulf of Mexico combined with the desert Southwest produces air masses that may create very strong thunderstorms, which in turn can produce very strong tornadoes in the traditional Tornado Alley, Friend said.

However, over the past several decades, Friend said, there has been an increase in the number of tornadoes in another region – the Southeast’s Dixie Alley, which includes Louisiana, Mississippi, Alabama, Tennessee and parts of Illinois.

The NIU study showed that although Dixie Alley is No. 2 overall in terms of tornadoes, this number has been increasing while the number of tornadoes in Tornado Alley is decreasing, Friend said.

To be prepared for a tornado event, Friend suggested keeping essential items packed in case of an emergency, including a whistle in case someone is trapped in a home.

In addition, he said, keeping tabs with the National Weather Service and other local weather detection agencies is important.

People should not rely on outdoor notification sirens, as they are primarily used to notify people who are outside, Friend said.