What is Snow Drought?
Snow drought is defined as period of abnormally low snowpack for the time of year, reflecting either below-normal cold-season precipitation (dry snow drought) or a lack of snow accumulation despite near-normal precipitation (warm snow drought), caused by warm temperatures and precipitation falling as rain rather than snow or unusually early snowmelt. (AMS Glossary of Meteorology)
Current situation and impacts in the West
June 7, 2018:
Most snow-monitoring sites have already melted out in Oregon, California, southern Idaho, Utah, Colorado, and northern New Mexico, and the remaining higher-elevation snowpack in these areas is well below normal, with many sites at less than 25% of normal. A sharp contrast is found in pockets of the northern Rockies where sites have well above normal snowpack though melting is underway rapidly due to well above normal temperatures throughout the month of May. In Alaska most sites have lost all snow cover and are not currently reporting with the exception of several sites in the southern coastal ranges to the south of Anchorage. Sites that are reporting in Alaska are well below normal. [Next update scheduled for June 21, 2018]
USDA Natural Resources Conservation Service (NRCS) percent of 1981-2010 median snow water equivalent (SWE) over the western U.S. (left/top) and Alaska (right/bottom) for June 3, 2018. Only stations with at least 20-years of data are shown. For an interactive version of this map, including percent of period of station record median SWE, please visitNRCS.
SNOw Data Assimilation System (SNODAS) percent of average (2003-2018) snow water equivalent (SWE) for June 02, 2018. Percent of average SNODAS processed using Climate Engine. Please note the shorter historical period of this dataset compared to the station data above.
SNOTEL basin-wide average SWE time series for the Klamath River Basin in Southern Oregon and Northern California. Black line is this year and red line is the 1981-2010 median. The regional SWE peaked in mid March, and is currently at only 11% of normal SWE for this date.