Melting ice makes Corps lakes unsafe

Published Feb. 25, 2011

ROCK ISLAND, Ill. – With late winter temperatures beginning to rise and fall, ice-covered areas on U.S. Army Corps of Engineers’ lakes are unsafe for winter activities.  Thin, rotten ice and ice unsupported by lake waters can give way at any time.  Venturing onto ice surfaces at Coralville Lake, Saylorville Lake and Lake Red Rock is extremely hazardous and is not recommended.

Ice Facts:

  • Corps lakes have a river running through them and never form stable ice.
  • Spring ice may collapse suddenly and without warning.
  • Spring ice is rotten ice.
  • Rotting ice begins to look grey and splotchy.
  • Once ice starts to rot, the thickness of ice cannot be used to determine if the ice is safe.  The ice may look solid – but beware.  Because of the way ice melts, the ice will dramatically weaken even as it retains much of its original thickness.
  • Ice can erode from the bottom up, with no obvious warning signs on top.
  • Melting upstream can create run-off that weakens river ice.
  • Ice near shore will melt more quickly.
  • Tree stumps, rocks and docks absorb heat from the sun, causing ice around them to melt.
  • Snow acts like an insulating blanket.  Ice under snow will be thinner and weaker.  A new snowfall can also insulate, warm-up and melt existing ice.
  • There is no such thing as 100 percent safe ice.  Ice is inconsistent.
  • The only safe ice-is the ice you stay off!

As lakes, ponds, streams and rivers throughout the Midwest begin to thaw, ice conditions will be very uncertain.  Although it may be tempting to venture out onto the ice for one last round of skating, hockey, ice fishing or other winter sport, it is highly recommended that all ice activity on Corps lakes is ended for the season.

For more information about the District’s reservoirs, visit the reservoir website on the WWW @:

Release no. 02/25/2011