For detailed coverage of local Flood Warnings visit the National Weather Service website HERE
Ice jams were big news this week, especially in Wilmington where the Kankakee River flooded parts of the city
Bitterly cold temperatures for roughly a week earlier this month led to rapid ice development on area rivers. That very cold spell was immediately followed by multiple rounds of rain and an extended stretch of above-freezing temperatures that caused the deep snowpack to melt. The water ran into area rivers, creeks, and streams, boosting the river levels and flooding already caused by the ice cover.
When ice breaks, it flows downstream. The ice can become lodged in tight or curved areas, against bridges or other obstructions.
The blockage reduces the river’s flow and causes flooding. If an ice jam breaks suddenly, it can release a surge of water that can cause flash flooding, like we saw on the Kankakee River in Wilmington on Friday.
Ice jams are pretty common on the Rock, Fox and Kankakee rivers. The National Weather Service says there’s a 50% chance of an ice jam on those rivers in any given year and there’s about a 1-in-3 chance of flooding caused by an ice jam in any given year.