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U.S. Army Corps of Engineers
St. Paul District
Public Affairs Office
332 Minnesota St., Suite E1500
St. Paul, MN 55101

Phone: (651) 290-5807
Fax: (651) 290-5752 


Wintertime river recreation and ever-changing ice conditions: know the risks

Published Jan. 7, 2019

ST. PAUL, Minn. – Given recent mild temperatures and the dynamic nature of moving water the U.S. Army Corps of Engineers, St. Paul District, reiterates that no ice is safe ice and conditions – particularly on the Mississippi River – are changing every day.

For those planning to enjoy winter outings on lakes and rivers, please remember common practices to reduce risk such as asking around locally about ice conditions, letting someone know your plan and bringing along/wearing appropriate safety equipment to include ice picks and flotation gear.

Conditions on the Mississippi River vary greatly with many factors affecting how ice forms and breaks up. Individuals using water vessels to access open water must continue to observe restricted areas below locks and dams.

Lakes and rivers are dynamic places with water currents, springs, water control structures, cattails, snow cover and many other factors affecting thickness. Many of these factors are hidden and difficult to see. Remember these guidelines for good, clear ice:


  • 4 inches can hold a person
  • 5-7 inches can hold a snowmobile or all-terrain vehicle
  • 8-12 inches can hold a car or small pickup
  • 12-15 inches can hold a medium truck

Remember that standing or parking in a group will require more ice than what is recommended in the guidelines.

Though the district does not measure ice thickness on any particular lake or river, by mid-February the St. Paul District should be underway with its annual ice survey on Lake Pepin, in Pool 4 of the Mississippi River, as the navigation industry begins planning for the new season. Once underway, results will be posted here:

Release no. 19-001