What SNOTEL is
SNOTEL is short for snow telemetry. It is a network of automated stations run by the USDA Natural Resources Conservation Service (NRCS) through its National Water and Climate Center. The stations sit in the mountains of the western United States and Alaska, often in remote spots at high elevation where the snow piles up. They run on their own all winter and send their readings in automatically, so nobody has to ski in to read a stake.
The network was built to forecast water supply. Much of the West’s water arrives as melting snow in spring, so knowing how much water is stored in the snowpack matters to farmers, cities and river managers. Skiers and riders get to use the same data, for free.
What a station measures
- Snow water equivalent (SWE): how much water the snow would make if it melted. Most stations measure it with a snow pillow, a flat bladder on the ground that weighs the snow sitting on it.
- Snow depth: how deep the snow is, measured at most stations by a sensor mounted above the ground.
- Precipitation: rain and melted snow caught in a gauge.
- Air temperature.
All of it is public. The NRCS publishes the readings through its Air and Water Database, which is where SnowBrains Weather gets them.
How we use SNOTEL on SnowBrains Weather
Observed snow on resort pages
When a resort has a good station nearby, its page can show new snow marked OBSERVED, which means it was measured at that station. We work it out from the change in the station’s snow depth over 24 hours. A station only counts if it is within 10 km (about 6 miles) of the resort, within 2,000 feet of its mid-mountain elevation, and not across a mountain range from it. If no station passes those tests, we don’t use one. An honest “no station” beats a far-off or wrong-side reading. The page names the station, its elevation and its distance, and links to it on the map.
The Snow Stations layer on the map
The map has a Snow Stations layer that shows the latest snow depth at SNOTEL stations, plus snow pillows run by other agencies that the NRCS also carries: California’s Department of Water Resources, British Columbia and Alberta. Raw sensors sometimes spike or drift, so we check every reading. We drop impossible values, smooth out sudden jumps, and leave off any station whose newest reading is too old.
The Snowpack page
The Snowpack page shows the NRCS maps built from SNOTEL: snow water equivalent as a percent of the 1991 to 2020 median, for the whole West and for 12 Western states. We save a fresh copy of each map once a day.
Grading our forecasts
The Accuracy page grades our saved forecasts against what stations measured: SNOTEL in the US and Environment Canada stations in Canada. A resort is only graded when a station sits within 15 miles of it and within 3,000 feet of its elevation.
What a station can and can’t tell you
A SNOTEL station is a careful measurement in one spot. It isn’t a measurement of the whole ski area. Keep these limits in mind:
- Location. The station may be a few miles from the lifts and at a different elevation, so it can get more or less snow than the slopes.
- Settling. Fresh snow settles under its own weight. A 24-hour change in depth can read lower than what fell, especially after a long storm.
- Wind. Wind can blow snow onto or off a station.
- Sensors. Instruments sometimes glitch. That is why we quality-check the readings, and why a single odd number is worth a second look.
That is why resort pages label every snow number. REPORTED comes from the resort’s own snow report, OBSERVED from a nearby station, and ESTIMATED from a weather model. When a resort reports its own numbers, that is the most authoritative word on what fell on the hill.
What about the East and Canada?
SNOTEL covers the western US and Alaska, so resorts in the East and Midwest don’t have SNOTEL stations nearby. In Canada and the East, recent snow on resort pages is either REPORTED by the resort or ESTIMATED from the forecast model, and the Snowpack page shows Environment Canada’s snow depth analysis and the British Columbia snow basin indices.
More guides: How to read a ski snow forecast · Snow and weather glossary · All our data sources