People fall through the ice all the time in the upper midwest, and every year a few die because they can't get back out. It happens so often because ice-fishing is a tradition -- you cut a hole in the ice and sit on a bucket and wait for a fish. They are supposedly "sweeter" when the water is cold. Real devotees build a little shack amd tow it out on the ice with their pickup trucks. They sit inside and drink cheap fruit brandy and schnapps. When the weather is warmer than usual, the news shows all warn fishermen not to take their trucks or shacks out on the ice, but some do anyway. Most of the time, of course, the fisherman who goes through the ice only gets one leg soaked, or it's a small hole and he can haul himself back out with or without his buddy's help, but every so often the whole truck goes through, or the ice is so mushy the edge of the hole keeps collapsing, or they foolishly fished alone, or they go unconscious from the cold, or, as seems to be the case in your story, they get under the ice and can't find their way back to the hole (more likely on a river than a lake). Seasonal articles about ice safety and how to rescue your fishing buddy are common. You don't live long in 40 degree water. When I lived in Wisconsin, I was interested to hear people use the phrase "going through" without ever providing an object for the preposition. If you say "my cousin went through last weekend" everyone knows you mean through the ice.