How to Identify Avalanche Terrain

Recognizing avalanche terrain is an essential skill. As you spend more time in the backcountry, this terrain recognition will help you to navigate a variety of conditions throughout the winter.

If there is ever a question on a backcountry day – a question about snowpack, a question about weather, strange group dynamics – terrain is the answer. We say this because you can control your exposure to avalanche hazard through terrain choice. There are days when you may choose to avoid avalanche terrain and days when you feel confident traveling in avalanche terrain.

Most slab avalanches occur on terrain that is between 30°-45°. Measuring slope angle is one thing that you can do as a backcountry traveler.

Other terrain features that are important to recognize are terrain traps. A terrain trap is any feature that increases the consequences of getting caught in an avalanche.

The basic understanding of avalanche terrain is a skill we hope to build in this lecture and in the field portion of your course. Let’s talk through essentials of terrain.

Now that you have a foundation for recognizing avalanche terrain, let’s talk about how you move through that terrain. What should you consider when you’re route finding going uphill, as well as when you are going downhill. We will discuss a few facets of backcountry travel techniques.

Introduction to JHAvalanche.org

The Bridger Teton Avalanche Forecast Center covers the mountains around Jackson and Alpine, WY. There are three forecast areas in this region – Teton Area, Togwotee Pass, and the Greys River Area.

The following video walks through the website in an effort to highlight the information that Sarah and others use on a daily basis.

Is this your forecast region? You can find it at jhavalanche.org.

Understanding Avalanche Problems

As a backcountry traveler, it should be our goal to avoid avalanches. Forecast centers often discuss current avalanche problems, where they are likely found, how sensitive to triggering they are, and how large of an avalanche this problem might produce.

Understanding current avalanche problems can help to hone in a daily route plan.

Watch this video explaining the avalanche problems forecast centers might identify in their daily forecasts.  

And here is a little deeper dive into specific avalanche problems:

North American Danger Scale

Each avalanche forecast offers a tremendous amount of information.  Most forecast centers offer daily danger ratings.  The danger scale goes from Low to Extreme, and offers a danger rating, commentary on the likelihood of triggering an avalanche, the size and distribution of avalanches, and travel advice.  

Here’s a great blog post from the Utah Avalanche Center about interpreting the danger rating.

Introduction to the Avalanche Forecast – Gathering Information from Forecasts

One resource that we will use whenever traveling in the backcountry is the local avalanche forecast page.  To locate your forecast center, go to avalanche.org and click on your local forecast center.

If you’re headed to Canada, you can go to avalanche.ca to find regional forecasts.

The avalanche forecast offers current hazard ratings, as well as any reports of recent avalanche activity, current and forecasted weather, and a variety of other information.

Avalanche Classification and Documentation

The avalanche vocabulary lesson continues. In the following video, Jake Hutchinson reviews how avalanches are documented, the shorthand codes, and the order of documentation.

Avalanches are documented in this order for consistency – TYPE, TRIGGER, SIZE, FAILURE PLANE.

Type of avalanche: Soft Slab, Hard Slab, Wet Slab, Loose, etc..

Trigger: There are 2 categories – Natural, Artificial. There are subcategories for artificial triggers including Skier, Snowboarder (rider), Snowmachine, Explosive, etc..

Size: This covers the destructive potential of the avalanche. The bigger the number, the bigger the avalanche.

Failure Layer: What did the avalanche fail on?

Avalanche Terminology – The Language of Snow

Many activities have their own vocabularies. The world of snow and avalanches is no different. Understanding this terminology is important as you read the avalanche forecast, communicate with fellow backcountry travelers, and submit observations to your local avalanche forecast center.

Avalanches are categorized as loose snow avalanches or slab avalanches.

When we are thinking about avalanche hazard, we often ask ‘Do we have the recipe for an avalanche?’ Is there a slab, a weak layer, and a bed surface on terrain that is steep enough to slide?

In the following video, Jake Hutchinson is going to dive deeper into some of the vocabulary of snow and avalanches.