More of a wilderness topic...
How thick does ice have to be on a frozen lake for it to be considered safe to walk on? I ask this because today I walked across my first frozen lake. It wasn't for fun, rather walking across it happened to be the most direct route to where we were going (it was Mitchell Lake, in the Indian Peaks, Colorado BTW). I knew the ice was solid because this particular area had not been above freezing for several weeks. There was about 8 inches of snow on top of the ice, and I stomped on it a bunch just to make sure to was good...solid as a rock. I think I heard once that ice that is 12 inches thick is strong enough to drive a truck on and I believe it. But what would be the minimum thickness safe enough for walking on?