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Flattop Mountain SNOTEL Snowpack: Water Year 2000

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These materials prepared by the Climate Change in Mountain Ecosystems Program -- U.S. Geological Survey, Glacier Field Station.  Dan Fagre, Program Coordinator, email: dan_fagre@usgs.gov.  For more information, visit the Glacier Field Station - Climate Change in Mountain Ecosystems program (CCME) web site. 


SNOTEL (SNOw TELemetry) sites are operated by the US Department of Agriculture, Natural Resources Conservation Service (NRCS) and used for forecasting water availability.  These stations measure Snow Water Equivalent (SWE), the weight of snow equivalent to inches of water, along with temperature and precipitation.  SWE is recorded daily at Flattop Mountain, located at approximately 6300 feet in elevation along the upper edge of the McDonald drainage in Glacier National Park, Montana (a second SNOTEL station is located in the Many Glacier valley).  The Flattop Mountain SNOTEL station has been in operation since October 1st, 1969.  To assist in calculation of water storage and availability during agricultural growing seasons, the data are compiled by water year (a water year runs from 1 October - 30 September).

The data plotted above includes: 30-year long-term average SWE - 1970-1999; the water year of maximum SWE - 1972; the water year of minimum SWE - 1992; the previous water year SWE - 1999; the current water year SWE - 2000, and the current snow depth. Water year 2000 proved to be a fairly mild winter with less than the mean SWE at Flattop Mountain. Temperatures at the Flattop Snotel site never dipped below 0 all winter. A spring storm on April 17 caught area residents off guard and showed up as an obvious spike in the SWE graph (43.2" SWE). This event marked the maximum snow water equivalent for water year 2000. Compared to the 30-year mean for maximum SWE at Flattop Mountain that typically occurs on the 27th of April (47.3" SWE), this year’s peak was about two weeks earlier, with 92% of mean SWE. This has been the first full winter with a snow depth sensor at Flattop Mountain - we hope this added data provided snow enthusiasts with valuable insights into snow water equivalent, depth, & density – and helped the snow fanatics plan for good powder days.