Rocks embedded in the base of a glacier grind against the underlying bedrock to create a fine grey rock powder (or "flour") which is carried away in strong winds and meltwater. Windborne rock flour from gigantic Kaskawulsh Glacier in Kluane National Park covers the gable logs of a cabin at the ghost town of Silver City on the south shore of Kluane Lake.
(Yukon, Alaska Highway, Silver City)