Retrogressive Thaw Slump
A slope failure diagnostic of thawing permafrost.
An open, cirque-shaped alcove bounded by a steep arcuate headwall overlooking slumped active layer material, mudflows, and debris flows and incised by thaw-water gullies.
Thermo-erosion retrogressive thaw slump
Thermo-abrasion retrogressive thaw slump
Terrestrial RTS occurs only in thawing permafrost (McRoberts and Morgenstern 1974; French 1996; Lantuit and Pollard 2005; Figs. 4 and 5). The scarp is created by thaw of ice-rich permafrost, the sloping debris lobe consisting of thaw-fluid falls, slumps, slides, and flows. As permafrost is exposed in this way, further thaw is enhanced, and the RTS expands headward by retrogressive thermo-erosion (Czudek and Demek 1970). RTS can form also as active layer detachments caused by deep seasonal thaw (Lewkowicz 1987...
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