A natural resource condition assessment for Sequoia and Kings Canyon National Parks: Appendix 4 – glaciers

Basagic, Hassan; Panek, Jeanne

Alpine glaciers provide ecological function through their effects on the hydrologic cycle, on terrestrial and aquatic microclimate, and on nutrient cycling. Sierra Nevada glaciers represent about 10% of total glacier area in the conterminous United States (Krimmel et al. 1998). Of Sierra Nevada glaciers, 469 of 1719 glaciers (27% of number), or 10.4 km2 of 39.2 km2 (27% of area) are in Sequoia and Kings Canyon National Parks1. Alpine glaciers occupy high elevation mountain cirques, typically on north and northeast aspects. Glaciers are located between 3,090 and 4,148 m (Raub et al. 2006). Glaciers delay peak runoff from spring to summer, when less water is available and demand is high, modulating seasonal variations in runoff (Fountain and Tangborn 1985). This is especially important in the Mediterranean climate of California where the bulk of precipitation falls between October and May, and the summer season is dry. Alpine glaciers also release nutrients and regulate water temperatures which effect aquatic and riparian flora and fauna (Brittain and Milner 2001, Dougall 2007). Like most alpine glaciers over the 20th century, SEKI glaciers have been receding in response to a warming climate (Oerlemans 2005), altering alpine hydrologic cycles and contributing to global sea level rise. The shrinkage of glaciers results in earlier spring runoff and drier summer conditions. So, while SEKI glaciers are important locally and represent some part of the total population of conterminous U.S. glaciers, their condition as well as their existence is severely threatened by climate change. This chapter will summarize recent work documenting Sierra Nevada glacier area loss, quantifying glacial retreat and determining which climate and topographic factors contribute most to Sierra Nevada glacial dynamics. This is intended to be brief, and provide an overview of what is known of SEKI glaciers.

A natural resource condition assessment for Sequoia and Kings Canyon National Parks: Appendix 4 – glaciers

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