The Mass Budget of Blue Glacier, Washington

Abstract

Blue Glacier has an area of 4.3 km.², a volume of 0.57 km.³, a mean density of 0.88 g. cm.⁻³and an altitude range of 1,275 to 2,350 m. above sea-level. It is an active temperate glacier in a strongly maritime climate where the net budget gradient varies from 10 mm. m.⁻¹in the ablation zone to 7 or 8 mm. m.⁻¹in the accumulation zone. There is a very large snow accumulation each winter and a large snow melt each summer which exceeds by several times the ice melt. The annual mass budget is strongly influenced by altitudes of the freezing level during spring and autumn storms, for these determine whether the heavy precipitation falls as rain or snow. Recent glacier variations are quantitatively consistent with climate trends but there is no clear cause-and-effect relation. Since 1958 the glacier has been gaining mass by an average of 0.4 per cent per year.