The Pokhara Valley: A Product of a Natural Catastrophe

Abstract

The Pokhara valley in the central part of Nepal is one of the few Himalayan intramontane valleys that permits one to decipher the way the landforms of the world’s highest mountain range evolve. The valley is attractive to tourists for the scenic majesty of its glaciated mountains, gorges, caves, and lakes, the formation of which results from a complex yet recent and dramatic evolution of the valley. For a long time, most of the inhabitants believed that the valley originated from the drying up of a huge lake similar to those of the Kathmandu and Kashmir valleys. Careful observations of the sediments filling the basin indicate that the Pokhara valley was affected by a giant, catastrophic debris flow five centuries ago. It is an emblematic site, where the steepness of the still rising front of the very Himalaya (“the abode of snow”) is maintained by sporadic collapses of the mountain walls controlled by a combination of both glacial and seismo-tectonic dynamics.