Estimating Snow Water Equivalent at NWS Climatological Stations

TitleEstimating Snow Water Equivalent at NWS Climatological Stations
Publication TypeConference Proceedings
Year of Conference2013
AuthorsFarnes, Phillip
Conference Name81st Annual Western Snow Conference
Series TitleProceedings of the Western Snow Conference
Date Published2013
Conference LocationJackson Hole, Wyoming
Keywordsdensity, precipitation, Snow water equivalent, snowmelt, temperature

Typically, National Weather Service (NWS) Climatological Stations measure snow depth but not snow water equivalent (SWE). However, SWE is generally more important than depth when used in hydrologic and wildlife studies. Typically, there are higher elevation stations that measure SWE but lower elevations stations are predominately Climatological stations that do not measure SWE. New snowfall densities are generally between 6 and 10 percent while snow packs can reach densities into the 25 to 35 percent range just prior to and during melt. As part of developing the climatic database for the core area of the Greater Yellowstone Area (GYA), daily SWE was computed for all Climatological Stations. Some of these stations have snow courses at or near the station. Also, snow measurements were made at some of these stations in conjunction with the Snow Sinking Studies on the Northern Range of Yellowstone National Park. Methods for computing daily SWE using snow depth, precipitation and temperature will be presented as well as comparisons between estimated SWE and measured SWE at ten stations. The lengths of records where both measured and estimated SWE exist vary from about 17 years up to about 75 years. Long range trends of SWE will be shown for stations with longer records.