Flattop Mountain SNOTEL Snowpack: Water Year 2009

Flattop Mountain SNOTEL Snowpack: Water Year 2009

These materials prepared by the Climate Change in Mountain Ecosystems program (CCME)-- U.S. Geological Survey, Northern Rocky Mountain, 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. 

The Flattop Mountain SNOTEL (SNOw TELemetry) station is one of nearly 600 similar stations operated throughout the western United States by the Natural Resources Conservations Service (NRCS, U.S. Department of Agriculture). These stations measure and record Snow Water Equivalent (SWE), which is the weight of snow water equivalent to inches of water. Most SNOTEL sites also measure temperature and precipitation; many now measure snow depth as well. Various agencies and organizations use the data from the stations to forecast water availability, floods, and avalanche hazard. 

The Flattop Mountain SNOTEL station has operated since October 1st, 1969. To help calculate water storage and availability during agricultural growing seasons, the data are compiled by water year; a water year runs from 1 October - 30 September. SWE records from the station extend for 33 water years (1970-2002). Precipitation records from the station start water year 1979, with temperature records starting water year 1983.

The Flattop Mountain SNOTEL station is located at approximately 6300 feet in elevation on Flattop Mountain, a high plateau between the Lewis and Livingston Ranges in Glacier National Park, Montana. The site is three air miles south of the Continental Divide. During the winter, complex combinations of weather and terrain determine snowfall at the site. Westerly weather systems predominate, bringing moisture from the Gulf of Alaska or Pacific Ocean. Less frequent northerly systems spill drier Arctic air through passes on the Continental Divide as they slide south along the Rocky Mountain Front. Flattop Mountain's position between the Livingston and Lewis Ranges amplifies the effect of these large-scale weather systems; the two ranges rise 2-4000 feet above the site and orographically wring moisture from both westerly and upslope easterly storms. Flattop Mountain is a useful indicator of snowfall throughout Glacier National Park because it is subject to the factors that influence conditions elsewhere in the park.

A graph comparing SWE for significant water years is below.

NOTE: A more detailed .PDF version of this graph is available for printing or viewing at SWE Comparison Graph.

The graph below shows the current water year SWE at Flattop Mountain along with snow depth and average daily temp:

NOTE: A .PDF version of this graph is available at SWE, depth and temperature.

For more information, see the climate prediction center's El Nino/ENSO Discussion.

Also available for viewing are graphs for:

• Water Year 2008
• Water Year 2007
• Water Year 2006
• Water Year 2005
• Water Year 2004
• Water Year 2003
• Water Year 2002
• Water Year 2001
• Water Year 2000
• Water Year 1999

Resources

• For details on how snowpack affects the spring opening of Logan Pass, visit our Spring Opening of the Going-to-the-Sun Road web page (Logan Pass is located at 6646 feet elevation along the upper edge of the McDonald drainage, approximately 10 miles southeast of the Flattop Mountain SNOTEL station).

• For the most recent SNOTEL data, graphs, and maps of snow distribution visit the Montana NRCS - Snow, Water, and Climate Services Snow Products web page – they provide snow depth! data for the Flattop Mountain SNOTEL station under the Daily Products-Reports heading.  Also, their detailed map of Montana SNOTEL sites is a great resource.

• The NRCS, National Water & Climate Center provides access to all SNOTEL data as well as in-depth publications describing the SNOTEL program.

• Avalanche forecasts for Flathead National Forest, Kootenai National Forest, & Glacier National Park can be found at the Glacier Country Avalanche Center, which also links to avalanche advisories for areas throughout the western US & Canada.

• For current & historic river level data, visit the USGS - Montana Current Streamflow Conditions web page.

Content Information Contact: Lisa_McKeon@usgs.gov