Ice Jam Flooding

The North Park Fire Department was up to their knees in icy water today as the Rock River backed up into dozens of homes. 13News Reporter Laura Gibbs reports that more than three dozen homes are flooded along Shore Drive in Machesney Park. Click here for her complete story. (Photos: Chris Anderson)

What is unique about ice jam flooding is the circumstance around how it forms. In most cases our beloved Rock River floods due to heavy rains and quick snowmelt.

Ice jam flooding is completely different. It doesn't occur because of an increase in water. It occurs because the channel is temporarily changed. Ice chunks that covered the Rock River up in Wisconsin last week broke up during last week's warm weather. As they floated southward into Northern Illinois this past weekend temperatures fell rapidly slowed everything down. Much like a pileup on a highway during fog, the river has essentially jammed up. Continued cold weather adds pressure to the mini-icebergs which forces the ice to heave up and down. This causes more of the water to be displaced, and more is forced onto the banks and into yards and basements.

The only way we're going to see this get better is by warming things up. Unfortunately that won't happen for at least three days. Additional flooding is expected before then! What's interesting with ice jam flooding is it will fluctuate greatly day-to-day so some houses may be dry tonight and completely surrounded by water tomorrow (another reason this is dangerous).

We'll have to keep monitoring the rain potential for Monday. If we don't have this ice jam flooding under control by then we may have a disaster in the works. Stay tuned!