Can avalanche activity alter the pattern of snowmelt runoff from high-mountain basins?

Avalanche activity can affect the subsequent generation of snowmelt runoff as a result ot two main changes occurring during avalanching: concentration of the snow mass, and an ambient temperature increase resulting from the avalanche’s fall to a lower elevation. The balance between these changes largely determines whether the rate of meltwater production from individual avalanche deposits is decreased or increased in comparison to undisturbed snow. Any noticeable effect on the temporal pattern of snowmelt runoff at the basin scale depends first on the proportion of the total basin snow cover which has been disturbed by avalanching, and second on the balance between delayed and accelerated meltwater production from all avalanche deposits in the basin in the basin. This paper discusses the effect of avalanche activity on runoff from a large (2500 sq km) basin in the Punjab Himalaya, Pakistan and ongoing research from small high-elevation basins in the Cascade Mountains, British Columbia.