A NEW INVENTORY OF SURGE-TYPE GLACIERS IN THE KARAKORAM HIMALAYA

Surge-type glaciers alternate between short periods of rapid advance and high surface velocities, and longer quiescent periods of terminus retreat and downwasting. They are relatively rare over the world as a whole, but there is a distinct clustering of them in locations such as Alaska, Svalbard and the Canadian High Arctic. Approximately 30 have previously been described in the Karakoram Himalaya. In this study we expand this number to almost 60 via the comparison of Declassified Intelligence Satellite Photography from the 1960s and Landsat imagery since the 1970s. This much larger concentration of surge-type glaciers than previously recognized is important to take into account when assessing their response to climate change. It can also provide new information on the likely factors driving glacier surging. To this end, analysis is currently being undertaken on the physical characteristics of these surge-type glaciers (e.g., length, area, aspect, elevation) compared to the population of glaciers in the Karakoram as a whole. Initial results indicate that glacier length is a dominant control on glacier surging, although not the only one.