However the waters at the shore near the West Thumb Geyser Basin are often open even during the winter. Hot water that pours from the geysers and pools mixes with the water of the lake and keeps it from freezing up. It is even possible to see river otters swimming in the open waters during the winter.
Tuesday, June 23, 2009
Even though it was already mid to late May when we visited Yellowstone National Park, Yellowstone Lake was still mostly frozen over. There was open water along most of the shoreline but the middle still had a ways to go to thaw out. Last year when we visited in May even less had thawed.