The Minnesota Department of Natural Resources has issued its annual ice safety warning for lakes with winter aeration systems.

Aeration creates areas of thin ice and open water that are extremely hazardous to people and pets. Open water areas can shift or change shapes, depending on weather conditions, and leaks may develop in air lines, creating other areas of weak ice or open water.

The updated list of aerated lakes and more information is available at mndnr.gov/eco/lakeaeration.

“We’re urging people to use caution anytime they venture onto lake ice, especially at night,” said Amanda Yourd, DNR hydrologist and aeration coordinator. “Extreme care should be taken on aerated lakes. Watch for the large orange and black warning signs at high-use public accesses and the required thin ice signs around open water areas.”

Aeration systems help prevent winterkill of fish populations by adding oxygen to the lake and, in certain situations, to protect shorelines from ice damage. They are generally operated from the time the lakes freeze until the ice breaks up in the spring. About 280 lakes will have aeration systems operating on them this winter. Private hatchery operators also use aeration systems, usually on small lakes without public accesses.

A permit from the DNR is required to install and operate an aeration system. Permit holders must publish public notices, post warning signs and inspect the systems at least once every seven days. Liability insurance is generally required of private groups or citizens operating aeration systems in protected waters. Watch for notices in local media identifying aerated lakes. DNR staff ensure permittees comply with all requirements and regularly inspect systems for safety.

Some municipalities may have ordinances that prohibit entering into the thin ice marked area and/or prohibit the night use of motorized vehicles on lakes with aeration systems in operation.  These local regulations are often posted at accesses where they apply.

Questions concerning aeration or thin ice can be answered by calling a regional or area fisheries office or the DNR at 888-646-6367.