Glaciers are one of the most valuable resources in the North Cascades National Park Service Complex (NOCA). Approximately one-third of all the glaciers in the lower 48 states are within the park (Post et al. 1971). The 312 glaciers in NOCA are a vital component of hydrologic systems and aquatic ecosystems. They also influence soil development, the distribution of vegetation, flooding and are dramatic indicators of climate change. The glacial resource is also central to the region's hydroelectric industry and our efforts to sustain endangered salmon and trout. Perhaps the most critical role of glaciers is providing cold fresh water during seasonal and interannual droughts, periods of low streamflow and high stream temperature. Glaciers provide 6-12% of the summer runoff of the Skagit River, the largest watershed in Puget Sound (Riedel and Larrabee, 2016).This role is becoming more important as snow-pack and glaciers decline. Since the late 1800's, approximately 56 percent of the park's ice cover has been lost during this time (Dick, 2013). In the Skagit River watershed this has resulted in a 25% reduction in summer streamflow since 1959 (Riedel and Larrabee, 2016)*.
To understand climate change, the glacier resource, and the effect of glaciers on other resources at NOCA, long-term monitoring of glaciers is needed. The National Park Service began long-term monitoring of glacier mass balance within NOCA in 1993. Mass balance monitoring includes direct field measurements of accumulation and melt to estimate the volume gained and lost on a seasonal and water-year basis. Noisy Creek, Silver Creek, and North Klawatti Glaciers have been monitored at NOCA since 1993 and a fourth glacier, Sandalee, since 1995. South Cascade Glacier, located just outside NOCA, has been monitored by the U.S.G.S. Water Resources Division since the mid-1950s. Each of these glaciers represents different characteristics of the greater glacier population, including geographic position, aspect and elevation. Since that time we have learned that each glacier in the North Cascades has a unique response to climate, but that all of the glaciers are retreating (Riedel and Larrabee 2011).
Four broad goals are identified to monitor glaciers as important vital signs of the ecological health of NOCA:
Riedel, J. and M. A. Larrabee. 2016. Impact of Recent Glacial Recession on Summer Streamflow in the Skagit River. Northwest Science, 90(1): 5-22.
Riedel, J. and M. A. Larrabee. 2011. North Cascades National Park Complex glacier mass balance monitoring annual report, water year 2009: North Coast and Cascades Network. Natural Resource Technical Report NPS/NCCN/NRTR--2011/483. National Park Service, Fort Collins, Colorado.
* Dick, K. A. 2013. Glacier change in the North Cascades, Washington: 1900-2009. Thesis. Portland State University, Portland, Oregon.
Last updated: January 19, 2018