Glaciers are water reservoirs that are sensitive to climate changes and important for water resources. In many applications, a realistic description of air temperature inversion is essential for accurate snow and glacier mass-balance simulations. To accomplish this we developed routines to simulate air temperature inversions in SnowModel, and used them to define spatial and temporal variations in glacier mass-balances. SnowModel is a physical spatially-distributed snow-evolution modeling system specifically designed for application in all landscapes, climates, and conditions where snow occurs. Using the new temperature inversion routines, SnowModel was used to simulate eight years (1998/99 through 2005/06) of snow accumulation and snow and glacier ice ablation in SW Ammassalik Island, SE Greenland. Nineteen glaciers were included in the simulation domain, including the Mittivakkat Glacier and other glaciers that could potentially provide water resources for the town Tasiilaq. The coastal areas around Ammassalik Island are strongly influenced by air temperature inversions, extending from sea level to approximately 300 m a.s.l. Modeled surface mass-balance for the glaciers averaged -650 mm w.eq. y^-1 for simulations that accounted for the inversions and -890 mm w.eq. y^-1 without the inversion routines. The difference in net glacier loss was 16.6 ×10⁶ m³ y^-1 for all glaciers; a 25% reduction in the simulated mass loss when the more realistic temperature inversions were included.