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Sunday, March 14, 2010

A lousy winter means trouble for glaciers and summer water supply

This is one of the driest, warmest winters I can remember in the past 25 years. It is disconcerting for a number of reasons: snow cover in to the summer provides natural bug suppression for those of us who like to hike and climb in the North Cascades, and it also provides for easier/better overland travel (at least I think so--scree is yuck). Snow also means easy water and workable high elevation bivvy spots (easy to mold snow in to a nice flat area).

But these are rather personal, subjective advantages of a healthy snowpack. The real importance of a good winter/big snowpack is (positive) mass-balance for the area glaciers, and the natural water storage and distribution represented. Streams and rivers across the state, and all who depend on them, from farmers to fish, receive a significant portion of their high-summer flow from snowmelt and glacier runoff. In the case of the Skykomish River, up to 35%! I hope to post a fact sheet on the Skykomish shortly.

Dr. Mauri Pelto, director of the North Cascades Glacier Climate Project, recently evaluated this winter's (lack of) snowpack in an email outlining the upcoming 2010 Field Season of research on 10 glaciers in the North Cascades:
"The winter of 2010 has been quite mild, with January setting a record high monthly mean temperature in the region and February the warmest since 1991. Precipitation has been below normal as well. This is leading to below average snowpack. The lower the elevation the greater the snowpack water deficit, 50% of average at Snoqualmie and 80% of average at Mount Baker. The lack of large storms has limited avalanching, thus avalanche fed glaciers are the most likely to have significantly below average snowpack. "

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