When I was in high school, I went metal detecting with my dad out in this state park. We were just looking for old homesteads. We never realized it had been a bombing range.
From 1949 to 1951, the Naval Reserve entered into a cooperative project with the Minnesota Department of Conservation. The goal of this project, known as Operation Woosh, was to produce wallowing holes for some 5,000 moose to help them find refuge from biting insects. The military dropped more than 50 live bombs, ranging in size from 500 to 2,000 pounds. As each bomb dropped, peat sprayed high into the air, instantly opening a pond up to 30 feet deep and 100 feet wide.
From Minesota DNR.