Avalanches
NAC · Updated Every 6 hours · Source: NAC
About Avalanches
Avalanches are rapid flows of snow down a slope that pose extreme hazards to backcountry travelers, ski areas, roads, and mountain communities. The western mountain ranges (Sierra Nevada, Cascades, Rocky Mountains) see the most significant avalanche activity, with danger levels fluctuating dramatically based on recent snowfall, wind loading, temperature changes, and the strength of buried weak snow layers.
Data Source
Avalanche danger forecasts are sourced from the National Avalanche Center's public API, which aggregates forecasts from all US avalanche centers (CAIC, NWAC, UAC, etc.). Forecasts are typically issued once daily by trained avalanche forecasters and cover elevation bands (below treeline, near treeline, above treeline) within each forecast zone. NWS winter alerts are retrieved from the api.weather.gov alerts endpoint.
| Detail | Value |
|---|---|
| Provider | National Avalanche Center / NOAA National Weather Service |
| Update Frequency | Every 6 hours |
| Coverage | United States (all 50 states and territories) |
| API / Data Feed | avalanche.org/v2/public/product and api.weather.gov |
What the Map Shows
Avalanche danger zones with current danger ratings (Low through Extreme) from NAC forecaster zones across western US mountain ranges, plus active NWS winter storm warnings, winter weather advisories, and blizzard warnings that indicate conditions favorable for avalanche formation.
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