The Editor,

The Journal of Glaciology

Sir, Subglacial stoping or block caving

The description of subglacial stoping or block caving of the Black Rapids Glacier in Alaska in the Journal of Glaciology, Vol. 2, No. 20, 1956, p. 727, reminds me of the almost identical conditions of the Kome Glacier on Nugssuaq Peninsula in the Umanaq District of western Greenland observed 27 years ago (Wissenschaftliche Ergebnisse der Deutschen Grönland-Expedition Alfred Wegener, 1929, und 1930/31, Bd. 3, 1935, p. 14). Lowering and rapid recession of the central part, caving in with crescent-shaped crevasses, a huge ice tunnel and a vigorous meandering melt water stream cutting through the ice were features of the Kome Glacier too. Such forms are probably created if the front parts of a glacier become stagnant and the destructive forces of melt water are no longer counteracted by the supply of ice from the higher parts of the glacier. These features represent a particularly strong development of a complex of forms which are typical of the ablation zone near the snout of glaciers (see R. v. Klebelsberg, Handbuch der Glaziologie und Glazialgeologie 1948, p. 122–139).