Snow hydrology of an alpine basin in the Sierra Nevada

Hydrologic and meteorologic observations at Emerald Lake in Sequoia National Park over a five-year period provide the first detailed description of the snow hydrology of an alpine basin in the Sierra Nevada. More than 95 percent of all precipitation was in the form of snow. Prolonged periods between storms permit sublimation losses to exceed 20 cm per winter, but little or no melt occurs during the winter in basins with northern exposure. Seasonal snow storage prior to spring melt ranged from 60 to 200 cm water equivalence. Average basin-wide snowmelt was about 1 to 1.5 cm per day in April and May and up to 3 cm per day in June and July. Peak snowmelt runoff exceeded 0.75 cm per day on at least 20 days per year. Instantaneous discharges rarely exceeded 0.5 cu m/sec/sq.km. More than 75 percent of the peak snowpack water equivalence and spring precipition became streamflow.