Locate focus areas in Alaska that span variation in temperature and precipitation across Alaska. • Estimate total gain or loss of water area between 1950 and present in aerial photographs and Landsat imagery. • Use temperature and precipitation data and estimates of evapotranspiration evaluate whether gain or loss of water can be explained by changes in thermal regimes (i.e., enhanced drainage associated with thawing of permafrost) or negative water balance (i.e., decreased precipitation or enhanced evapotranspiration).