(Spirit Lake, IA) — The Iowa Department of Natural Resources is urging caution after a snowmobile and an ATV broke through the ice on West and East Lake Okoboji. The incidents happened Thursday night and the riders were rescued by people ice fishing and treated and released from the hospital. The DNR’s Greg Harson says the ice quality on the Iowa Great Lakes isn’t as good as it has been in the past. Harson says the new snow is going to make it harder to identify ice heaves and locations where geese are keeping the water open. He recommends checking the ice thickness frequently and bringing ice picks, a throwable floatation cushion and 50 feet of rope.