The distribution and flow characteristics of surge-type glaciers in the Canadian High Arctic

dA systematic review of 1959/60 aerial photography, and 1999/2000 Landsat 7 imagery, has identified 51 surge-type polythermal glaciers in the Canadian High Arctic. These were identified from the presence of features such as looped medial moraines, intense folding visible at the surface, rapid terminus advance, heavy surface crevassing, and high surface velocities. These observations suggest that surging glaciers are much more common than previously believed in the Canadian High Arctic, where only six surge-type glaciers have previously been described. Of the 51 surge-type glaciers identified in this study, 15 were observed in the active phase in the 1959/60 and/or 1999/2000 imagery. The most dramatic advances have occurred on western Axel Heiberg Island, where Iceberg, "Good Friday Bay" and Airdrop Glaciers have all advanced by 4-7 km between 1959 and 1999. For glaciers with repeat Landsat 7 coverage from 1999 and 2000, image correlation software was used to determine the magnitude and spatial distribution of surge velocities. For example, "Mittie" Glacier on Manson Icefield was moving at a rate of up to 1 km a(-1) over a distance of at least 25 kin back from its terminus. The terminus of this glacier has advanced by at least 4 km since 1959, and the glacier was observed to be heavily crevassed during overflights in April 2000, with clear signs of surface lowering of 10-25 in indicated by a strandline.