All but the newest arrivals to Central Illinois are certain this region receives more than its fair share of tough winter weather. And they are right.
When it comes to ice, Central Illinois is second to none. That’s what the scientists at the Prairie Research Institute of the Illinois State Water Survey (ISWS) discovered.
“Central Illinois has the distinction of being in the nation’s primary area for severe freezing rain (ice) storms,” the ISWS stated. Of course, this is not something the tourism, real estate or chamber crowd care to acknowledge let alone brag about.
According to ISWS historical data, our region averages five days with freezing rain every winter. The high risk band runs from Pike, Cass, Morgan and Scott counties northeast to Iroquois and Vermilion counties. Typically, Illinois experiences 15 severe ice storms each decade. That adds up to a lot of power outages.
On average, the state as a whole experiences five severe winter storms every year. ISWS defines a severe winter storm as one that produces six or more inches of snow in 48 hours or less, or damaging ice accumulations. The storm must impact an area of at least 5,000 square miles.
Our winter storms usually begin as low pressure systems in the Pacific Ocean or Asia. While most of these systems run out of steam in the Rockies, a few do redevelop east of the mountains. ISWS scientists have found the most favored redevelopment area is Colorado and the surrounding region. To a lesser extent, our storms may form in Alberta, Canada or along the Gulf Coast in Texas.
Looking at Central Illinois, we average about 1.5 severe storms per year. By contrast, Northwest Illinois leads the state with an average of 2.4 storms per year. And they can keep them.
The ISWS scientists say severe winter storms are most likely to occur in January, though the earliest severe winter storm took place on Oct. 28-30, 1925, while the latest struck on May 1-2, 1929. If you like to play the historical odds, severe winter storms are most likely to strike on Dec. 24-26 and March 2 and 3. The winter of 1977-78 produced a record number of severe winter storms in our state – 18 to be exact. That winter claimed 62 lives.
On the other hand, ISWS discovered severe winter storms are least likely to strike on Dec. 2-4 and 15-16, Jan. 3-5 and 23-28, Feb. 20-24 and March 15-17 and 21-24. Of course, severe storms can (and do) occur on these dates, but less frequently.
Despite advances in weather forecasting, long-range forecasting of severe winter weather is not yet possible. Even when storms begin to take shape, forecasting the severity and areas of highest impact seems to be more art than a science.
One thing is certain, severe winter weather will continue to be a part of life in Illinois. Since severe winter storms can’t be prevented, the experienced Illinoisan knows there is but one certain way to beat the worst of what winter has to offer – follow the ducks to someplace warm.