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South Sister


South Sister had twelve glaciers, seven of which were named. Going clockwise around the peak from the south aspect, these are:

The extent of glaciers on South Sister is based on photographs from the 1950s. Lower at left is a satellite image from September 2021 showing the current extent of ice. 


The U.S.G.S. mapped several separate glaciers as one glacier, hence the separation of Carver and Skinner into three ice bodies each.

South Sister has experienced extensive glacier loss. Clark, Eugene, South Skinner, South Carver, and North Carver have all stagnated and ceased to flow.


Unlike other volcanos of Oregon, one unofficial glacier is still active on South Sister: Ruspen. We discovered this glacier on the north side of South Sister above the Skinner glacier group. It is still very much an active glacier and is the most resilient to climate change.

Looking at the recent satellite image, Prouty is not noticeable due to high amounts of rock fall and the lack of an accumulation zone. While large in area, it is thinning towards stagnation and may not be a glacier in the near future.

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