As temperatures drop below freezing, some folks are eager to get out on the lake for ice fishing. However, authorities are warning anglers to be careful of the thin ice.

The Minnesota Department of Natural Resources says everyone should be cautious on ice, especially on lakes that use aeration systems for circulation. These systems can cause ice to be thinner than usual and may even create areas of open water.

Lakes that use aeration systems are usually posted with “warning” and “thin ice” signs.

Aeration systems are generally operated from the time lakes freeze until ice breaks-up in the spring. They help keep fish from dying during the winter.