August 1990: The view southwest down the Crescent glacier on the south flank of Mount Redoubt. A hot pyroclastic surge during the eruption of Dec. 15, 1989 caused thick snowpack on the upper volcano flank to avalanche and partly melt. The glacier in the right middleground is blanketed (dark material at surface) by an an unusual ice diamict emplaced during the eruption.

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