| In the North Cascades of Washington, from 1977 to 1988 winter precipitation has been 15% below the long term mean and summer temperature has been 0.9{dollar}spcirc{dollar}C above the long term mean. The North Cascade Glacier Climate Project was founded in 1984 to determine the effect of this climate change on North Cascade glaciers, by monitoring the terminus behavior, mass balance, and runoff of numerous North Cascade glaciers. In order to measure the mass balance on numerous glaciers, the traditional mass balance measurement methods have been streamlined. An unusually high density of measurements is achieved by reliance on rapid measurement techniques, such as crevasse stratigraphy, probing and ablation stakes. The accuracy of the annual balance determination on a given glacier is +0.15 m.; The mass balance has been measured directly on ten glaciers annually. The mean annual balance from 1984 through 1988 has been {dollar}-{dollar}0.12 m/a, {dollar}pm{dollar}0.07.; The terminus behavior of 107 North Cascade glaciers has been monitored. During the 1984 through 1988 period 90 glaciers retreated, 3 advanced and 14 have been in equilibrium.; Correlation of glacier mass balance and local weather records indicates that North Cascade glaciers can be divided into 6 groups based on glacier sensitivity to ablation season temperature, accumulation season precipitation, summer cloud cover and May and October freezing levels. The climatic sensitivity group of each glacier is determined by a glacier's topographic characteristics and geographic location, and can be determined using geographic analysis.; North Cascade glaciers provide 25-30% of the region's summer runoff. The timing and magnitude of this runoff is controlled by mass balance fluctuations. As mass balance increases, glacier meltwater storage capacity increases. The greater a glacier's storage capacity the longer the delay between glacier runoff and non-glacier runoff, resulting in higher late summer water supply. The recent decrease in glacier meltwater storage capacity has caused earlier peak glacier runoff, reducing late summer water supply.; The need to properly manage regional water resources requires monitoring the mass balance and behavior of North Cascade glaciers. |
