On May 18, 1980, after nearly 2 months of local
earthquakes and steam eruptions, ice-clad Mount St. Helens in the Cascade
Range, southwesternWashington, began a major explosive
eruption, directed first northward and then upward. The lateral blast, occuring in only the first few minutes of a 9-hour
continuous eruption, devastated more than 150 km2 of forest and
recreation area and left 60 people dead. The huge debris avalanche that
immediately preceded the eruption and the intermittent eruptions during the
following three days removed about 2.9 km3; this comprised new magmatic material and material from the old upper and
northern part of the mountain, including about 40 to 45 Mio m3 of
glacial snow and ice.
Damage
��������
devastated
more than 150 km2 of forest and recreation area and left 60 people
dead
Data source
Haeberli, W., M�ller, P.
(1988): Fluctuations of Glaciers 1980�1985, Vol. V International Association of
Hydrological Science.
Remarks
Shoestring Glacier, which had already been
investigated before the eruption, lost major parts of ist
accumulation area.