Safety officials continue to warn about the dangers of thin ice as Minnesota’s lakes start to freeze, especially the danger on lakes with aeration systems. Aerators are installed on around 280 Minnesota lakes to help prevent winterkill of fish. But they also create areas of open water and thin ice. Those aeration open water areas can shift or change shapes depending on weather conditions as well, and leaks may develop in air lines, creating new areas of weak ice or open water. Aerated lakes are required to have warning signs at all commonly used access points, along with thin ice signs marking the area’s perimeter. Aerated lakes in the local area include: Clear, Hanska and Sleepy Eye in Brown County, Marion, Swan and Winsted in McLeod County, Silver Lake in Sibley County, and Fedji, Kansas, and St. James Lakes in Watonwan County.