By Philip Kedrowski Redleaf Consulting
Because Big Sky receives a lot of snow, structures here must be designed to account for the additional weight. The weight of snow on the ground, expressed in pounds per square foot, is referred to as “ground snow load.”
A structural engineer must know the ground snow load when designing a building. In order to determine snow depth and density, the Natural Resources Conservation Service (NRCS) and the National Weather Service (NWS) have monitoring stations strategically located throughout the state. Between the NRCS and NWS, there are a total of 294 stations in Montana. The three closest to Big Sky are located near Lone Mountain, Shower Falls and Carrot Basin.
Data is recorded at each station and is available to the public at no charge. However, the engineer can’t use this data directly – it must be statistically processed in order to estimate the 50-year ground snow load at each station location. As more data is recorded each year, the estimations become increasingly accurate.
Once the ground snow load is determined at each monitoring site, the ground snow load at any location is determined by interpolating between these known snow loads. The school of engineering at Montana State University created and maintains a website where users enter a geographic location in Montana and the interpolation is performed automatically, free of charge. This is a tremendous contribution to the safety of structures in Montana.
The Civil Engineering Department accepts donations for this service. Visit coe.montana.edu/snowload/ for details.
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Nearby SNOTEL sites
Site Name /Type /Latitude /Longitude /Elevation /Duration Monitored
Lone Mountain /NRCS – SNOTEL /45.28° -111.43° /8,880 ft /21 years
Shower Falls /NRCS – SNOTEL /45.40° -110.96° /8,100 ft /34 years
Carrot Basin /NRCS – SNOTEL /44.96° -111.29° /9,000 ft /30 years
Find more information at the following websites:
NRCS SNOTEL sites – wcc.nrcs.usda.gov/snotel/Montana/montana.html
Montana Ground Snow Load Finder – coe.montana.edu/snowload/
Philip Kedrowski, PE, LEED-AP, is owner/engineer of Redleaf Consulting, PLLC. Redleaf is the only engineering company based in Big Sky.
