Cedar Rapids Facing Localized Flooding Due to an Ice Jam, DNR Cautions Others Near Rivers
Thursday, March 14, 2013 by Iowa DNR
CEDAR RAPIDS — Localized flooding is occurring in the city of Cedar Rapids about one-third of a mile upstream from where the Interstate 380 bridge crosses the river.
The flooding is caused by an ice jam that has built up in the river and has closed some local roads. The city has dropped the water levels at the 5-in-1 dam below the ice jam in an attempt to increase flows and reduce the upstream flooding depths.
In other areas, Iowans should be alert for localized ice jams as the weather warms and river ice begins to break up. Thick layers of ice can break into chunks, float downstream and stack up against bridges, culverts, woody debris or sharp bends in the river. There are no effective man-made solutions to ice jams. The jams can form and break up in a few hours or last several days.
There is little danger as long as the water continues to flow. If the water is blocked, it can rise very quickly and the height of the flood cannot be anticipated. Unlike other flood events, floods caused by ice jams can be unpredictable and localized. Ice jams can occur on a sunny day when people least expect flooding.
People who live or work in low-lying areas near streams should be aware of possible obstructions downstream—such as a low-lying bridge or a tree jammed against a bridge. Heavy rainfall and warm temperatures can cause ice to break up, move and jam.
Watch the river, too, because flooding from ice jams tends to be so localized that it may not appear on radar screens. You may be the first to see there’s a problem.
It pays to be prepared with an evacuation plan in this situation. If an ice jam and flooding occur, act quickly to move yourself, your family and your valuables to safety. Then notify the police or sheriff’s office to close roads or help others evacuate.