What Is Snowfield?
Snowfield AI provides real-time snow condition forecasts for 110+ ski resorts across the United States, British Columbia (Canada), and Switzerland. We combine measured data from government-operated weather stations with forecast models to give skiers and snowboarders accurate, up-to-date conditions.
Data Sources
We pull from six primary data sources, each with different coverage and measurement types:
| Source | Coverage | Data Type | Quality |
|---|---|---|---|
| SNOTEL | Western US (800+ stations) | Automated snow pillows & precipitation gauges | Measured |
| SnoCountry | Eastern US resorts | Resort-reported snow conditions | Reported |
| BC ASWS | British Columbia, Canada | Government automated snow stations | Measured |
| SLF IMIS | Swiss Alps (189 stations) | Automated snow depth, temperature, wind | Measured |
| NWS | United States | Temperature, precipitation, wind forecasts | Forecast |
| Open-Meteo | Worldwide | Extended forecast models (7+ day) | Estimated |
How We Measure Snow
Snow Depth
Snow depth is the total amount of snow on the ground, measured from the surface to the base. In the Western US, SNOTEL stations use automated snow pillows that measure the weight of the snowpack. In Switzerland, SLF IMIS stations use ultrasonic sensors. In British Columbia, BC ASWS stations provide automated measurements. These are all direct, physical measurements — not estimates.
Fresh Snowfall (24-hour)
Fresh snow is measured as the change in snow depth over the past 24 hours at SNOTEL, BC ASWS, and SLF IMIS stations. For Eastern US resorts, SnoCountry provides resort-reported fresh snowfall numbers. When no measured data is available, we estimate using precipitation forecasts and snow-to-liquid ratios — but always label these clearly as estimates.
Snow Water Equivalent (SWE)
SNOTEL stations measure SWE, which tells you the water content of the snowpack. This is important for understanding snow density — light powder has a low SWE-to-depth ratio, while heavy wet snow has a high ratio.
Temperature & Wind
Current and forecasted temperature comes from the National Weather Service (NWS) for US resorts, supplemented by Open-Meteo for international locations. Wind data comes from the same sources and is particularly important for wind chill and avalanche conditions.
Data Quality Indicators
Every data point on Snowfield has a quality indicator so you always know the confidence level:
- Measured — Direct readings from automated weather stations (SNOTEL, BC ASWS, SLF IMIS). Highest reliability.
- Reported — Resort-reported conditions (SnoCountry). Reliable but may lag behind real-time changes.
- Forecast — Weather model predictions (NWS, Open-Meteo). Accuracy decreases with forecast range.
- Estimated — Calculated from available data when direct measurements aren't available. Always marked with
~and "est" label.
Regional Coverage
Western United States
The most comprehensive coverage. SNOTEL provides measured snow data for nearly every major ski resort in California, Colorado, Utah, Montana, Wyoming, Idaho, Washington, Oregon, and New Mexico. NWS provides forecasts.
Eastern United States
Eastern resorts (Vermont, New Hampshire, Maine, New York, West Virginia) use SnoCountry for resort-reported conditions. There is no SNOTEL coverage east of the Rockies, so fresh snow measurements rely on resort reporting.
British Columbia, Canada
BC Government automated weather stations (BC ASWS) provide measured snow data for major BC ski resorts including Whistler, Revelstoke, and others. Avalanche data is sourced from Avalanche Canada.
Switzerland
The Swiss Federal Institute for Snow and Avalanche Research (SLF) operates 189 IMIS stations across the Swiss Alps. These provide high-quality measured snow depth, temperature, and wind data. SLF also publishes avalanche bulletins twice daily.
Update Frequency
| Data Type | Update Interval |
|---|---|
| SNOTEL measurements | Hourly (may appear delayed by 1-2 hours) |
| SnoCountry reports | Daily (typically morning) |
| BC ASWS measurements | Hourly |
| SLF IMIS measurements | Every 30 minutes |
| NWS forecasts | Every 1-3 hours |
| Open-Meteo forecasts | Every 3-6 hours |
| Snowfield cache refresh | Every 30 minutes |
Frequently Asked Questions
Why does my resort show estimated data?
Not all resorts have a nearby SNOTEL, BC ASWS, or SLF IMIS station. When a resort
is far from any measurement station, we fall back to weather model estimates. These are
clearly labeled with a ~ prefix and "est" badge.
Why is the snow depth different from the resort's website?
Resorts often measure at the summit or a specific location, while SNOTEL stations may be at a different elevation. Our data reflects the nearest automated measurement station, which may differ from the resort's chosen measurement point.
How accurate are the forecasts?
Our 24-hour forecasts are generally very reliable, sourced from the NWS. Accuracy naturally decreases beyond 3-4 days. We show up to 12 days of forecast data but recommend focusing on the first 3-4 days for trip planning.
Why don't you show avalanche data for all resorts?
Avalanche data is currently available for British Columbia (via Avalanche Canada) and Switzerland (via SLF). US avalanche center data integration is planned for future updates.
API Access
Snowfield data is available via JSON API for developers and AI agents:
GET /api/weather/{resort-slug}— Full weather data for a resortGET /api/locations— List of all active resorts with coordinatesGET /llms.txt— Machine-readable site description for AI agents
Each API response includes source attribution, data quality scores, and timestamps.