The Geomorphology and Morphometry of Glacial and Nival Areas

Abstract

Glacial and nival hydrology is particularly sensitive to temperature and radiation, and hence latitude, altitude, and aspect are especially important influences on glacial and nival landforms. The latitudinal sequence polar ice-cap, polar desert, tundra, boreal forest is matched by the altitudinal zonation nival, sub-nival, alpine, sub-alpine, although high altitudes differ from high latitudes in the relationship of seasonal and diurnal fluctuations and in radiation, wind, and weather. A cirque is defined morphologically as a large steep-sided hollow, open on the downstream side but essentially closed upstream by a steep, arcuate headwall below a divide; its floor slopes more gently than its sides, and also more gently than the succeeding slope downstream. Although nivation is important early in the transformation of a steep gully or landslide scar into a cirque, most nivation hollows are on a much smaller scale, and lack the initial relief to accumulate sufficient snow to develop into cirques.