CHICAGO, IL – As an Arctic air mass sweeps into Illinois, a high risk of ice formation on area rivers presents a threat of ice jams and potential localized flooding, particularly along the Kankakee and Illinois Rivers.
A passing cold front will bring light snow to parts of the region during the late night and afternoon on Tuesday. According to the US National Weather Service Chicago Illinois, conditions will then turn significantly colder for Wednesday night through Friday morning, with wind chills as low as -15 to -20 expected at times. The bitter cold is anticipated to last through Thursday night.
The rapid onset of freezing temperatures raises the likelihood of ice formation on area rivers. This could lead to freeze-up ice jams and potential localized flooding on rivers such as the Kankakee River and the Illinois River. Ice jams can form when chunks of river ice accumulate at obstructions like river bends or bridges, effectively acting as a dam. This can cause water levels to rise rapidly upstream, resulting in severe local flooding. Areas along the Kankakee River, specifically near Wilmington, Illinois, have a history of experiencing ice jam-related flooding.
Sub-zero overnight lows are forecast for both Wednesday and Thursday nights, creating ideal conditions for rapid ice development. Residents living along the banks of the Kankakee and Illinois Rivers should be prepared for rapidly changing river conditions and the possibility of sudden floodwaters, particularly in low-lying, flood-prone areas.
