Snowpack
Western U.S. by State
Snow on the Ground, Coast to Coast
Canada
What the snowpack maps show
Snowpack is the snow that has built up on the ground over the season. A single storm makes headlines, but the snowpack tells you how the whole winter is going: how deep the base is likely to be, how much terrain is filling in, and how the season compares with a normal year.
Where the maps come from
The Westwide map and the 11 Western state maps and Alaska’s come from the USDA Natural Resources Conservation Service (NRCS), built from its automated SNOTEL stations high in the mountains. They show snow water equivalent, the amount of water held in the snow, as a percent of the 1991 to 2020 median for the same date. We save a fresh copy of each map once a day, and each card links to the live NRCS map. The national snow depth and snow water equivalent maps come from NOAA’s National Operational Hydrologic Remote Sensing Center (NOHRSC). Canadian snow depth comes from Environment and Climate Change Canada’s daily snow analysis, and the British Columbia basin indices come from the BC River Forecast Centre.
What is snow water equivalent?
It is how much water you would get if you melted the snow. A foot of light, cold powder might hold under an inch of water, while a foot of dense spring snow holds much more. Measuring water instead of depth makes years and places easier to compare.
What does 120% mean?
The stations in that area hold 120% of the median snow water equivalent for this date, measured over 1991 to 2020. 100% is a typical year to date. It says nothing about how the snow skis, only how much water is stored in it.
Why do early-season percentages swing so much?
Early in the season the median is small, so one storm can push a basin to 200% or more, and a dry week can drop it fast. The percentages settle down as winter goes on.
Why is there no SNOTEL map for the East or for Canada?
SNOTEL covers the western US and Alaska. For the rest of the country, the NOAA snow depth map shows snow on the ground coast to coast. Canada has its own networks, which is why we show Environment Canada’s snow depth map and the BC basin indices.
Guides: What SNOTEL stations are · How to read a ski snow forecast · Snow and weather glossary