Avalanche Terrain Education

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Avalanche Terrain Exposure Scale (ATES)

The potential for avalanche danger can be found in a range of terrain from flat valley bottoms to mellow hills and steep slopes. Backcountry travel in any season poses risks, and anyone who travels into the backcountry, especially during the winter months, must accept and be prepared for the risk associated with their travel choices.

This page is a resource for you to learn all about the Avalanche Terrain Exposure Scale (ATES) and how to use it.

The Avalanche Terrain Exposure Scale (ATES) is a planning tool that was designed and developed extensively by Parks Canada as a way to help recreationists and professionals understand the risks that inherently come with travel in avalanche terrain. We believe that the ATES scale is an extremely valuable tool and are excited to see its use spread throughout the United States, New Zealand, and Europe. We are also grateful to Parks Canada for being such generous and willing collaborators in this endeavor.

It is an ongoing goal of Beacon Guidebooks to engage the backcountry ski community in education and awareness of the ATES system and to continually improve the accuracy and functionality of ATES mapping in the United States.

THE NEWLY RELEASED ATES 2.0 SCALE (2023) HAS CHANGED FROM A THREE-POINT SCALE TO A FOUR-POINT SCALE AND UPDATING ALL EDUCATIONAL RESOURCES TO MATCH THE NEW SCALE IS A WORK IN PROGRESS. JOIN OUR NEWSLETTER TO STAY INFORMED AS MORE INFORMATION IS RELEASED.

Anyone wanting to venture into the backcountry should seek out proper avalanche training from a professional before they go. If you feel inexperienced, confused, concerned or timid about traveling in the backcountry, it is wise to seek a professionally certified guide.

Get started with your avalanche training with these links:

Avalanche Terrain Exposure Scale (ATES)
Categories At A Glance

ATES 1
Simple

Exposure to low-angle or primarily forested terrain. Some forest openings may involve the runout zones of infrequent avalanches and terrain traps may exist. Many options to reduce or eliminate exposure.

ATES 2
Challenging

Exposure to well-defined avalanche paths, starting zones, terrain traps and/or overhead hazards. Options exist to reduce or eliminate exposure with careful route-finding.

ATES 3
Complex

Exposure to multiple overlapping avalanche paths or large expanses of steep, open terrain. Frequent exposure to overhead hazard. Many avalanche starting zones and terrain traps with minimal options to reduce exposure.

ATES 4
Extreme

Exposure to very steep faces with cliffs, spines, couloirs, crevasses or sustained overhead hazard. No options to reduce exposure; even small avalanches can be fatal.

What Is The ATES Scale?

The Avalanche Terrain Exposure Scale, or ATES, is a system of rating backcountry terrain based on your exposure to potential avalanches when traveling in that terrain. It is a scale designed to be used concurrently with the weather, snowpack, and avalanche risk forecasts for the area you are planning to tour. While the weather and snowpack change continually, the terrain generally remains the same and can be evaluated independently. When you consider and evaluate the terrain in addition to these other variables, you can do a lot to mitigate your exposure to avalanches.

How Does It Work?

The updated 2.0 ATES scale (2023) divides terrain into four categories: simple (green), challenging (blue), complex (black), and extreme (red). These four categories should not be confused with the beginner/ intermediate/ expert terrain ratings that are common to most ski areas in North America, even though they share colors. For example, an area that is rated as ATES 2 (challenging terrain) does not mean that it is an appropriate place for an intermediate skier to be traveling just because it is blue. The characteristics of each of the ATES categories should be studied and applied specifically as they relate to the avalanche exposure of the terrain, not to the ability or skills of the skier.

How Do We Rate Terrain?

The ATES ratings in the Beacon Guidebooks products are created by a team using a technical model of 11 weighted measures that are used to evaluate both the overall zone as well as individual runs within that zone. It is helpful to understand each of the rating categories so that you can determine if it is an appropriate place for you and your group to be traveling. Advanced training and experience is required to use the ATES criteria to make your own judgments of the terrain as it relates to avalanche hazards.

Avalanche Terrain exposure scale (ATES)

In-Depth Explanations and Examples

ATES 1: Simple

Many options to reduce or eliminate exposure

DESCRIPTION

Exposure to low angle or primarily forested terrain. Some forest openings may involve the runout zones of infrequent avalanches and terrain traps may exist. No glacier travel.

Under most conditions, you can move confidently through SIMPLE terrain. It is still important to watch out for small slopes with terrain traps, openings in forests, and exposure to avalanche paths from above.

How much experience do I need for SIMPLE terrain?

SIMPLE (Class 1) terrain requires common sense, proper equipment, first aid skills, and the discipline to respect avalanche warnings. Simple terrain is usually low avalanche risk, ideal for novices gaining backcountry experience. These trips may not be entirely free from avalanche hazards, and on days when the Backcountry Avalanche Advisory is rated ‘Considerable’ or higher, you may want to re-think any backcountry travel that has exposure to avalanches – stick to groomed x-country trails, or within the boundaries of a ski resort.

ATES 2: Challenging

Options exist to reduce or eliminate exposure with careful route-finding

DESCRIPTION

Exposure to well-defined avalanche paths, starting zones, terrain traps and/or overhead hazards. Glacier travel is straightforward but crevasse hazards may exist.

Travel in CHALLENGING terrain requires a more thoughtful approach, including a thorough assessment of conditions. Big slopes with serious consequences exist, so you will need good travel techniques to travel through them, and under some conditions they should be avoided entirely. There will be frequent points at which travel decisions will need to be made to manage risk based on the current conditions and options available.

How much experience do I need for CHALLENGING terrain?

CHALLENGING (Class 2) terrain requires skills to recognize and avoid avalanche prone terrain – big slopes exist on these trips. You must also know how to understand avalanche danger forecasts, perform avalanche self rescue, basic first aid, and be confident in your route-finding skills. You should take an Avalanche Skills Training Level 1 and 2 course prior to traveling in this type of terrain. If you are unsure of your own, or your group’s ability to navigate through avalanche terrain – consider hiring a professional, IFMGA or other certified guide.

ATES 3: Complex

Minimal options to reduce exposure

DESCRIPTION

Travel in COMPLEX terrain requires a thorough assessment of conditions, advanced route-finding and terrain-assessment skills, and a diligent approach to all aspects of avalanche risk management. If you lack experience or are unsure of your skills, it is best to stay out of complex terrain unless conditions are entirely favorable. If this is the type of terrain you seek out, be patient and wait for the right conditions.

How much experience do I need for COMPLEX terrain?

COMPLEX (Class 3) terrain demands a strong group that is up for the task, aware of the risk and has years of critical decision-making experience in avalanche terrain. There can be no safe options on these trips, forcing exposure to big slopes. A recommended minimum is that you have taken an Avalanche Skill Training Level 2 course or beyond. Be prepared! This is serious country – not a place to consider unless you’re confident in the skills of your group. If you are uncertain – consider hiring a professional, IFMGA or other certified guide.

ATES 4: Extreme

No options to reduce exposure

DESCRIPTION

Exposure to very steep faces with cliffs, spines, couloirs, crevasses or sustained overhead hazard. No options to reduce exposure; even small avalanches can be fatal. Technical glacier travel with extensive crevasse bands or icefalls.

Travel in extreme terrain requires a thorough assessment of conditions, expert route-finding and terrain-assessment skills, and a diligent approach to all aspects of avalanche risk management. Extreme terrain is appropriate for expert and experienced ski mountaineers only.

How much experience do I need for EXTREME terrain?

EXTREME (Class 4) terrain demands an expert group that is up for the task, aware of the risk, and has years of critical decision-making experience in avalanche terrain. There can be no safe options on these trips, forcing exposure to big slopes and high-consequence hazards. Be prepared! This is serious country – not a place to consider unless you’re confident in the skills of your group and the conditions. Even minor mistakes or poor decision-making in this terrain can be disastrous. If you are uncertain – consider hiring a professional, IFMGA or other certified guide.

Parks Canada Agency, Government of Canada. “Avalanche Terrain Ratings for Backcountry Touring in the Mountain National Parks.” Parks Canada, 6 Nov. 2017, https://www.pc.gc.ca/en/pn-np/mtn/securiteenmontagne-mountainsafety/avalanche/echelle-ratings/EETA-ATES-2.

Learn more about ATES

With Creator Grant Statham

Grant Statham is the Snow Safety Director for Parks Canada and the developer of the ATES model. Here he discusses how ATES works and gives great examples of each classification of terrain.

Play Video

Avalanche.org

Click here for an excerpt about ATES from their Avalanche Encyclopedia

The High Route

Click here for a blog post about the newest release of ATES 2.0 at the International Snow Science Workshop in Bend, OR, 2023

onX Backcountry

Watch this ATES tutorial video from onX Backcountry. Also, check out the ATES Education page on onX Backcountry.com

How do I use the ATES scale?

The Avaluator Trip Planner is a comparative chart that crosses the avalanche danger ratings with the terrain ratings and gives a reference point by which you can decide if your planned trip is still in the comfort zone of your entire group. It does not predict the stability of the snowpack. The Avaluator is a trip-planning tool and is best used both before the start of a trip as well as in the field, given that snowpack and weather conditions can be dynamic.

“The Avaluator.” Avalanche Canada, https://www.avalanche.ca/pages/avaluator.

Remember, just because you are in the “green” area of the Avaluator doesn’t mean you are completely safe. 25% of historical accidents have occurred in this zone. Be on the watch for isolated avalanche conditions.

Your Daily Process

1. Get the Forecast

Always obtain up-to-date avalanche danger forecasts for the area you plan to ski. Know what the danger rating is for that day and that particular zone. Use the highest danger rating given for that area for that day. Remember, avalanche forecasts cover very large areas. You need to verify the danger level at the start of and during your day by observing snow conditions and making your own assessments.

2. Plan Your Trip

Review and assess the terrain that you plan on traveling using one of the route-planning tools at your disposal (guidebooks, maps, apps, etc.) Be sure to use elevation-specific terrain ratings. Once you know and understand the danger forecast and the ATES rating for the zone and individual runs you plan to ski, use the Avalulator Trip Planner to compare and evaluate these two risk variables. This, along with other factors influencing your group (energy levels, skier skills, weather conditions, etc.) should be used to inform your decision making.

3. Check Your Gear
4. Verify Conditions
5. Use Good Travel Habits
6. Evaluate Slopes
7. Reflect on Your Day

It should be understood that anomalies in avalanche terrain and avalanche conditions may exist. Users of all of these trip-planning tools (avalanche danger forecasts, ATES ratings, Avaluator Trip Planner) assume their own risk. Users must continue to assess both the terrain and the conditions at all times while traveling in the backcountry and be prepared to make in-the-moment observations and decisions accordingly.

“Chapter 6: The Daily Process.” Avalanche Canada’s Online Avalanche Tutorial, https://avysavvy.avalanche.ca/en-ca/the-daily-process.

Travel Smart. Ski Smart.

Disclaimer

Read and understand this warning before using any Beacon Guidebooks publication.

Winter travel in mountainous terrain, including skiing, snowboarding, snowmobiling and climbing, is dangerous in nature and can result in serious injury or death. It is up to the users of this information to learn the necessary skills for safe backcountry travel, access additional trip planning materials and to exercise caution while traveling in the backcountry.

Beacon Guidebooks has made an effort to confirm that the information in their publications is correct. High Point Productions, LLC; DBA Beacon Guidebooks is in no way responsible for damage to property, personal injury, trespassing or violation of law in conjunction with the use of their publications. User accepts and takes responsibility for all risks. Discrepancies between trail and route location and actual may exist. Beacon Guidebooks publications do not depict private property. Routes drawn do not imply that public access is available. Information is subject to change faster than can be updated. Liability is expressly disclaimed.

This education page is intended to add to your collective avalanche education, but it is not a replacement for a full avalanche education course with professionals.

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Avalanche Terrain Education

Avalanche Terrain Exposure Scale (ATES)