Permafrost thawing is increasing in the Arctic and sub-Arctic [Osterkamp and Romanovsky, 1996; Osterkamp, 2007] in response to climate warming [Hassol, 2004]. One consequence of thawing permafrost is the development of thermokarst (physical depression of ground surface) because of reduced support of overlying soil [Jorgenson et al., 2006]. Thermokarst lakes, for example, result from changes to surface energy balance, which drive permafrost thaw locally, such that a topographic depression develops and captures water, forming a lake or pond. Climate warming of the past several decades is expected to increase the occurrence of thermokarst. For example, Agafonov et al. [2004] have noted that the rate of expansion of a single thermokarst depression in western Siberia has increased in the latter half of the twentieth century, coincident with increasing air temperature and precipitation during the thaw season.