Estimating localized SWE on the Yellowstone northern range

After the large fires of 1988 in Yellowstone National Park, many projects were initiated to study their effects. One of the studies involved the effects of fire on vegetation and ungulates on the northern winter range.Because snow water equivalent (SWE) is a significant factor in animal foraging and movement, it was necessary to develop a method that could use data from National Weather Service (NWS) climatological stations and Soil Conservation Service (SCS) snow courses and SNOTEL (SNOw Survey TELemetry) sites to predict SWE in areas of varying slopes, aspect, elevation, and forest cover. It was first necessary to estimate SWE at NWS climatic stations. The daily snow depth, precipitation and temperature values were used to estimate daily SWE. Daily SNOTEL SWE was used to estimate daily SWE at SCS snow courses. Algorithms were developed to estimate daily SWE for flat and open areas on the northern range not having significant drifting similar to data collection sites.A multidimensional nomograph was developed from measured data to estimate SWE for any slope and aspect within the northern range area. The habitat cover type was used to adjust SWE for forested areas.Techniques and relationships developed for the northern range would be transferable to other intermountain areas that accumulate a winter snowpack and that have daily climatic and/or snow pillow data.