Avalanche forecasts
None of the 84 forecast zones on avalanche.org carries a current danger rating: every center is between seasons. Daily forecasts usually run from about December to April; each zone's page says when its last forecast was issued and carries any statement its center has out now.
Avalanche danger on the map
Every forecast zone, in its highest rating for the day while the rating is current. Alaska’s zones are northwest of the frame. Select a zone for its forecast.
- 1 Low
- 2 Moderate
- 3 Considerable
- 4 High
- 5 Extreme
- Information, no rating
- No current forecast
By center
Each center and its zones, with today’s rating where one is current.
What this means
| Danger level | Travel advice | Likelihood of avalanches | Size and distribution |
|---|---|---|---|
| 1 Low | Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. | Natural and human-triggered avalanches unlikely. | Small avalanches in isolated areas or extreme terrain. |
| 2 Moderate | Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. | Natural avalanches unlikely; human-triggered avalanches possible. | Small avalanches in specific areas; or large avalanches in isolated areas. |
| 3 Considerable | Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding and conservative decision-making essential. | Natural avalanches possible; human-triggered avalanches likely. | Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. |
| 4 High | Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. | Natural avalanches likely; human-triggered avalanches very likely. | Large avalanches in many areas; or very large avalanches in specific areas. |
| 5 Extreme | Avoid all avalanche terrain. | Natural and human-triggered avalanches certain. | Large to very large avalanches in many areas. |
The ratings are the North American Public Avalanche Danger Scale, the five levels every US and Canadian avalanche center forecasts in. A center rates each elevation band of a zone separately: above treeline (the alpine), near treeline, and below treeline, because wind, sun and snow differ with height. The zone's color on a map is its highest band. A forecast is issued in the morning for that day and expires, usually that evening or the next morning; after that it says nothing about the snow, which is why this site never shows a rating past its expiry.
An avalanche problem is what the center expects to release: its type (wind slab, storm slab, persistent slab, deep persistent slab, wet slab, loose dry, loose wet, cornice, glide), where on the mountain (aspect and elevation), how likely it is to be triggered, and how large it could be, on the destructive size scale from D1 (relatively harmless to people) to D5 (the largest known).
Most avalanches that catch people release on slopes of 30 to 45 degrees. The live map's slope angle layer shades those slopes, so the terrain a forecast warns about can be found on a map before a trip.
Forecasts from the US avalanche centers, published through avalanche.org, the National Avalanche Center’s public service. Avalanche forecasts describe general conditions across a whole zone. They cannot say whether one slope is safe: that takes avalanche training, rescue gear, and your own observations. Weather from the National Weather Service; snowpack from USDA NRCS SNOTEL.