NRCS Snow Survey Data

Snow surveys in the West date back to around 1906, when the University of Nevada's Dr. James Church laid out the first western snow course. Dr. Church also invented key sampling procedures and equipment. A snow course is a permanent site where manual measurements of snow depth and snow water equivalent are taken by trained observers. Measurements are usually taken around the first of the month during the winter and spring. Generally, the courses are about 1,000 feet long and are situated in small meadows protected from the wind. Snow survey data can be used to help determine the weight the snowpack exerts on the ground at the site in that area or elevation zone. To determine the snow load, one needs to know how much the snowpack weighs. The weight of the snow varies with water content of the snowpack. The snow water equivalent (SWE) or water content of the snowpack, is the amount of water in the snowpack measured in inches if you were to melt the snowpack.