AlbertaParksca

Alberta Parks

Kananaskis Country Avalanche Terrain Ratings Scale (ATES)

    Avalanches are a natural phenomenon that occurs in the mountainous region of Kananaskis Country. While more common in the winter months, they can occur at any time of year if there is snow on the ground. 

    Avalanche potential is directly linked to the terrain that the snow falls on. As the terrain gets steeper the potential for avalanches increases and the public must make an assessment how and where they plan on going in the terrain. 

    The Avalanche Terrain Exposure Scale (ATES) was developed to help persons recreating in the terrain make better evaluations of the risk that are inherent with travelling in avalanche terrain. 

    Avalanche Terrain Classification

    The current Avalanche terrain ratings are broken down into two different classifications, a public model and a technical model. While both present similar information, the technical model includes a much more detailed version of the terrain while the public model presents a more concepts based approach to the technical model. 

    The information is presented in a few different formats. It is commonly taught on avalanche courses such as the Avalanche Skills Training level 1 and 2 as well as in guide book and on a few apps that have been presented by developers. 

    On this page the terrain was evaluated using computer modeling that evaluated slope angle, tree cover and estimated run out length. Many areas of the map have not been ground-truthed and due to the computer modelling nature of the map, there may be errors. 

    The map is intended to be used as a high level overview for overall trip planning. Detailed decisions that are more specific to individual terrain features must still be evaluated by users in the field.

    Exposure

    The ATES is designed to categorize avalanche exposure based on the configuration of the terrain. By using the ATES, backcountry travelers, including skiers, boarders and waterfall ice and mixed ice climbers, will have improved their understanding of the type of avalanche terrain that threatens their proposed outing.

    The ATES works by applying the information provided in the Public Avalanche Forecasts for the park you plan to visit, in combination with Avalanche Terrain Ratings that have been configured for many of the most popular trails and routes in that park.

    You can then use that information to help you evaluate the avalanche hazard of your intended route, and also to help you select appropriate trip routes and destinations based on the terrain ratings and current conditions.

    ATES Communication & Technical Models

    Model for Backcountry Travel

    Terrain Rating

    Class

    Description for Backcountry travel

    Non-Avalanche

    0

    No known exposure to avalanches. Very low-angle or densely forested slopes located well away from avalanche paths, or designated trails/routes with no exposure to avalanches.

    Simple

    1

    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.

    Challenging

    2

    Exposure to well-defined avalanche paths, starting zones, terrain traps or overhead hazard. With careful route finding, some options will exist to reduce or eliminate exposure.

    Complex

    3

    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.

    Extreme

    4

    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.

    Model for Waterfall Ice Climbing

    Terrain Rating

    Class

    Description for Waterfall Ice Climbing

    Non-Avalanche

    0

    Routes with no exposure to avalanches except small sluffs and spindrift.

    Simple

    1

    Routes with brief exposure to very low frequency avalanches starting from above or crossing occasional short slopes.

    Challenging

    2

    Routes with long exposure to low frequency avalanches or brief exposure to high frequency avalanches starting from above or crossing a few short slopes. Options to reduce exposure.

    Complex

    3

    Routes with long exposure to high frequency avalanches starting from above or crossing steep slopes with terrain traps below. Minimal options to reduce exposure.

    Extreme

    4

    Routes with long and sustained exposure to very high frequency avalanches starting from above and crossing multiple steep slopes with terrain traps below. No options to reduce exposure.

    Technical Model

     

    Class 0
    Non-Avalanche Terrain*

    Class 1
    Simple Terrain

    Class 2
    Challenging Terrain

    Class 3
    Complex Terrain

    Class 4
    Extreme Terrain

    Exposure

    No known exposure to avalanche paths

    Minimal exposure crossing low- frequency runout zones or short slopes

    only

    Intermittent exposure managing a single path or paths with separation

    Frequent exposure to starting zones, tracks or multiple overlapping paths

    Sustained exposure within or immediately below starting zones

    Slope angle
    and
    Forest density

    Very low-angle (< 10°) open terrain or steeper areas of dense forest

    Low-angle (< 20°) terrain or steeper slopes in dense forest with openings for runout zones or short slopes

    Moderate-angle (< 30°) open or gladed terrain with some open slopes or glades > 35°

    Moderate to high-angle (< 35°) terrain with a large proportion of open slopes > 35° and some isolated glades or tree bands

    High-angle, open terrain averaging > 35° with a large proportion of slopes > 45° and few or no trees

    Slope shape

    Straightforward, flat or undulating terrain

    Straightforward undulating terrain

    Mostly planar with isolated convex or unsupported slopes

    Convoluted open slopes with intricate and varied terrain shapes

    Intricate, often cliffy terrain with couloirs, spines and/or overhung by cornices

    Terrain traps

    No avalanche-related terrain traps

    Occasional creek beds, tree wells or drop-offs

    Single slopes above gullies or risk of impact into trees or rocks

    Multiple slopes above gullies and/or risk of impact into trees, rocks or crevasses

    Steep faces with cliffs, cornices, crevasses and/or risk of impact into trees or rocks

    Frequency- magnitude
    (avalanches:years)

    Never

    1:100 - 1:30 for

    ≥ Size 2

    1:1 for < Size 2

    1:30 - 1:3 for ≥ Size 2

    1:1 for < Size 3

    1:1 for ≥ Size 3

    10:1 for ≤ Size 2

    > 1:1 for > Size 2

    Starting zone size
    and density

    No known starting zones

    Runout zones only except for isolated, small starting zones with ˂ Size 2 potential

    Isolated starting zones with ≤ Size 3 potential or several start zones with ≤ Size 2 potential

    Multiple starting zones capable of producing avalanches of all sizes

    Many very large starting zones capable of producing avalanches of all sizes

    Runout zone
    characteristics

    No known runout zones

    Clear boundaries, gentle transitions, smooth runouts, no connection to starting zones above

    Abrupt transitions, confined runouts, long connection to starting zones above

    Multiple converging paths, confined runouts, connected to starting zones above

    Steep fans, confined gullies, cliffs, crevasses, starting zones directly overhead

    Route options

    Designated trails or low- angle areas with many options

    Numerous, terrain allows multiple choices; route often obvious

    A selection of choices of varying exposure; options exist to avoid avalanche paths

    Limited options to reduce exposure; avoidance not possible

    No options to reduce exposure

     

    Backcountry Travel Model Waterfall Ice Climbing Model Technical Model

    Using the ATES Scale

    Terrain is highly variable and as a result, elements of terrain may fit into multiple classes. Applying a terrain exposure rating involves considering all of the variable described in the technical model above. Some aspects of terrain though are default priorities. 

    Terrain that qualifies under an italicized descriptor automatically defaults into that or a higher terrain class. Non-italicized descriptors carry less weight and will not trigger a default, but must be considered in combination with the other factors.

    ATES Feedback Survey

     

Simple
Challenging
Complex
Extreme
Areas within these zones are managed by the leaseholder.
Pan: Left-click and drag. Zoom: Scroll wheel. Tilt & Rotate: Right-click and drag.

Gallery

Aster Lake region, Simple Terrain Avalanche At treeline near Burstall Pass, Challenging Terrain Avalanche below treeline near Commonwealth Creek in terrain trap Cegnfs Bowl, Complex Terrain Commonwealth Ridge, Complex Terrain Headwall Bowl, Complex Terrain Highwood Pass, Complex Terrain Miners Gully Canmore, Extreme Terrain (note avalanche and tracks visible) Mountain Rescue Program staff doing snow profile Murray Moraines, Complex Terrain Murrays Moraines, Complex Terrain Parallel Falls WI4, Extreme Terrain Purple Col, Complex Terrain Skier approaching col Skier in Complex Terrain Skiers on Robertson Glacier, Complex Terrain Snow profile Cegnfs Bowl, Complex Terrain Tent Ridge, Complex Terrain Tent Ridge size 4 avalanche, Complex Terrain Warspite Bowl, Complex Terrain Warspite bowl, Complex Terrain (1)

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Updated: Mar 20, 2025