The Western US depends heavily on the seasonal snowpack stored in mountainous regions to provide water to its rapidly growing population. Even modest decreases in the long-term amount of runoff from melting snow that reaches the lowlands will have severe impacts on >70 million people, threatening drinking water availability and imperiling tens of billions of dollars in commerce. Therefore, in a warming climate, it is essential to examine the state of the snowpack in the region to detect long-term trends as they emerge.
This research will do so using two datasets. The SNOw TELemetry (SNOTEL) network consists of automated stations that collect liquid-equivalent precipitation, snow depth, and snow-water-equivalent (SWE) data at over 800 sites, with a period of record spanning 50 years at many sites. The snow course data are manual monthly observations of SWE gathered by hand at set locations, with periods of record of 80 years or more at many sites.
The variables used to assess the state of the snowpack in the SNOTEL data each year include the peak SWE value, the date at which peak SWE is reached, and the date that the snowpack melts out. Future work will consider the fraction of precipitation that falls as rain versus snow. The snow course data is only one measurement near the turn of each month, so the available variables for each year are limited to the mean SWE value each month and the peak SWE.