Cataloguing Retrogressive Thaw Slumps along the Old Crow River, YT: Proposing Regional Controls on Retrogressive Thaw Slump Formation and Growth

Abstract

The Old Crow River flows across a continuous permafrost zone in the Northern Yukon. The seasonally frozen ground contains ice, organics, and metal pollutants. Retrogressive thaw slumps form when permafrost on the riverbanks thaw and sediment flows downslope into the river, leaving an unvegetated scar that can be seen on satellite images. The thaw slump will grow rapidly until stabilization impedes further melt. The specific controls on permafrost thaw will vary regionally throughout the Yukon, and the variables affecting formation and activity of thaw slumps along the Old Crow River have not been studied. Influences on the activity of thaw slumps are proposed through cataloguing geomorphic conditions and variables measured using satellite images and digital elevation data. The data collected suggests that cliff slope and direction, river processes, and proximity to certain landforms may influence growth and activity of thaw slumps along the Old Crow River. Satellite data is used to perform a supervised classification of the area that identifies RTS with a sensitivity of 62% and precision of 85%.

Department: Physical Sciences

Faculty Mentor: Dr. Robin Woywitka