Unstable Ice on Coralville Reservoir

Published Jan. 7, 2016
Iowa City, IA - The U.S. Army Corps of Engineers is warning individuals to be careful on frozen lakes. Due to heavy precipitation during the month of December, the Coralville Lake level is currently more than 10 feet above the normal elevation for this time of year. This high water level during the winter is extremely unusual and brings with it some very real hidden dangers. As of 5 January, the water levels are falling almost one foot per day. With colder temperatures, ice has begun to form along the shoreline and in the bays. The combination of ice formation and receding water creates unstable and dangerous conditions. Ice that is not supported by lake water is at risk of cracking, breaking or giving away at any time. As the ice shelf begins to drop, it can cause a dangerous slope along the shoreline making it hard to get back off the ice. With the water levels being higher, this is much steeper than it normally would be. Ice could also break away from the shoreline creating a floating mat with no way to get back to shore. The worst case scenario would be the development of an ice bridge where there is an air pocket created between the ice and surface of the water. This condition is extremely unstable no matter how thick the ice may be and falling through it in this situation leaves little chance for escape and makes a successful rescue next to impossible. Due to these unsafe conditions, the public is advised to stay off Coralville Lake.

Contact the Coralville Lake Administration Office at (319) 338-3543 extension 6300 for more information on lake levels, outflows and inflows.

Release no. 16-005