Mass Balance Studies on the Hintereisferner, Ötztal Alps, 1952–1961

Abstract

Investigations of the mass balance of the Hintereisferner are dealt with for the period 1952–61. Ablation of ice was measured with stakes, ten of which per square kilometre were considered as a sufficient number. The area of ice ablation terminates in the “zero-line of ice ablation”. The net accumulation was studied in pits, and by mapping of enduring accumulation patterns. In order to avoid errors it is proposed that the term “firn line” be replaced by the term “old snow line”. This would more clearly emphasize that only the net accumulation of old snow from the current budget year is a gain of mass for the glacier. The term “firn”, in accordance: with Flint’s [1957] definition should be used only for snow more than one year old. Between the old snow line and the zero-line of ice ablation in some years an appreciable firn ablation takes place. The mass balance reveals a large variation between +0 77×10⁶m.³ of water in the most favourable budget year 1954–55, and −9.83×10⁶m.³ of water in the most unfavourable budget year 1957–58. The average annual mass balance was −3.60×10⁶m³ of water, with an estimated maximum possible error of about ±0.54×10⁶m³ of water.