Just a Short walk from our campsite in the park was this quiet cove on the southern edge of Lake Yellowstone a large deep water lake that is large enough to make its own weather. It is at about 7000 feet altitude and gets very cold in winter (-50 degrees F) and yet has thermal hot springs feeding it hundreds of feet below. In spit of the thermal activity the water temperature is very cold and the lake freezes in winter. There are gysers (photos to be added) along the shore and below the water. The lake and most of the park are located in the crater of a volcano that errupted 625 million years ago.