Danger Scale

Your starting point for understanding the day’s hazard

We use the North American Public Avalanche Danger Scale to rate avalanche danger and provide general travel advice based on the likelihood, size, and distribution of expected avalanches. The danger scale consists of five levels, from low to extreme. Danger ratings often vary between our forecast zones and elevation bands.

Categorizing avalanches based on their physical attributes and travel management techniques

We use nine avalanche problem types to describe the character of the avalanches that we expect to be the most likely and/or dangerous each day. Infographics show the distribution, likelihood, and size of each problem. We also include a brief discussion and visual media from the field.

Avalanche Problems

Our daily fieldwork involves traveling throughout our 1.2 million-acre region to observe changing conditions. At the end of each day, we submit a report following the Snow, Weather, and Avalanche Guidelines (SWAG).

We log roughly 500 observations from staff, partner organizations, and the public each winter on our website. These descriptions of snow conditions, reports of triggered and natural avalanches, and images from the field help us verify—or question—our assessment of conditions. Along with data from weather stations and models, these observations are the basis for the avalanche forecast.

The observations database should be a resource for you, too. As you prepare for a trip, we recommend checking to see if there are any recent reports from the area you’re planning to visit.

We issue special alert products when large avalanches are very likely or certain in many areas and when unusually dangerous avalanche conditions exist. These products are disseminated through various emergency alert systems to inform people who might otherwise not be tuned into the avalanche forecast.

An Avalanche Watch is issued when dangerous avalanche conditions will develop in 24- 48 hours. Be prepared to adjust your plans. When an Avalanche Warning is issued, dangerous avalanche conditions currently exist and we recommend that you avoid avalanche terrain until conditions improve.

Watch: We have all the ingredients to make tacos.
Warning: We’re making tacos now!

The Special Avalanche Bulletin is issued when significant public use is expected and dangerous avalanche conditions exist, but the avalanche conditions do not merit an Avalanche Warning.

Before and after the daily forecast season, we may issue conditions updates two or three times per week. These products discuss avalanche conditions and weather factors but do not have a danger rating or avalanche problems.

In the daily forecast, many technical terms are hyperlinked to entries on the National Avalanche Center’s Encyclopedia. Visit this resource to learn about a wide range of topics.

Operational Partners