Glaciological Studies on Mount Wrangell, Alaska, 1961

Snow pit studies (3 to 4 m. deep, extended by core drilling to 10 m.) involving temperature, density, hardness and stratigraphy profiles were made at 5 locations in the caldera and an adjacent snow-filled crater. The facies para- meters calculated for the summit area of Mount Wrangell (4,000 to 4,300 m. at 62"N.) compare well with the same parameters near the dry-snow line on the Greenland Ice Sheet. The mean annual temperature, based on measurements 10 m. below the snow surface in the centres of the caldera and inactive craters, is "20°C. Effects of volcanic heating were observed near the edge of the caldera. Accumula- tion was abnormally high during the 1961 summer. It varies markedly with topog- raphy and the mean annual value exceeds 100 cm. water equivalent in smooth central areas of the caldera and adjacent craters. Surface velocity was measured by triangulation on a network of poles from control points on the caldera rim; the average value in the caldera was about 5 cm. day-1 or about 20 m. yr.-l.