Thermokarst or Permafrost Lake on the Denali Highway, Alaska

This is a thermokarst lake, or permafrost collapse lake on the Denali Highway near the Thompson River. Thermokarst means “heat hole.” The icicles are just what happens in the fall in Alaska. The rug-like material draping over the edge of the collapse crater is tundra, here composed mostly of mosses and lichens.