On the Canwell Glacier where the edge of the southern moraine meets exposed ice. Channels typically form next to moraines like this and since this is very near the toe of the glacier it's had a long time to form this deep channel.

canyonmoraineeastern alaska rangeiceovercasthikecanwell glaciermountainssummeralaskahikingdayhikealaska rangeglacier

From Dayhike on the Canwell Glacier | 2014-07-23