During the spring months in areas where rivers freeze over, there is a natural disaster that can occur called an Ice Jam. These occur when a sudden warm spell causes snowmelt, often combined with heavy rains, causing rivers to swell and break the ice cap on the river in to various sized chunks. As the ice starts to move, it jams where the river bends or narrows, or against man made structures such as road or train crossings. These ice jams then cause the river to back up and not allow the water to flow, resulting in extreme flooding.
According to FEMA, “Ice jams cause approximately $125 million in damages annually including $50 million in personal property damage.”
I have had personal involvement with ice jams while serving in the Coast Guard as part of a helicopter crew. During the 1997 and 2001 ice jam flooding along the Rock River in Illinois, our crew had to rescue dozens of people, often from rooftops.
Please see my photos of the 2001 jam here, and watch my video below. Sorry for the self promotion.