New Zealand Mountan Safety Council

Online Course - Terrain - ATES

Avalanche Terrain Exposure Scale

Before you head out for a trip, do you know what kind of terrain you will encounter? Good trip planning should tell you whether you will be in Avalanche terrain, and if there are options that allow you to stay clear of it. Some terrain is more complex and committing than others, and might not offer alternatives.

When planning your trip, read the guidebook, study maps and photos, talk to friends, check weather and avalanche conditions, and refer to the ATES ratings. This combination will give you a better sense of the route you are choosing.


How much experience do I need for the trip I am planning?

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 people gaining backcountry experience.
  • These trips may not be entirely free from avalanche hazards. 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, e.g. stay within the boundaries of a ski area.
  • Recommended minimum course – Avalanche Awareness (1and a 1/2 days)
Challenging terrain
  • Challenging (Class 2) terrain requires skills to recognise and avoid avalanche-prone terrain - big slopes exist on these trips. You must also know how to understand avalanche advisories, perform avalanche self rescue, basic first aid, and be confident in your route-finding skills.
  • In places where an avalanche advisory exists, you should take an avalanche course prior to travelling in this type of terrain.
  • Recommended minimum course – Backcountry Avalanche Course (4 days)
  • If you are unsure of your own, or your group’s ability to navigate through avalanche terrain - consider hiring a professional NZMGA qualified guide.
Complex terrain
  • Complex (Class 3) terrain demands a strong group with 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, or someone in your group, should have taken a four-day avalanche course and have several years of backcountry experience. Be prepared! Check the avalanche advisory regularly, and ensure everyone in your group is up for the task and aware of the risk.
  • Recommended minimum course – Backcountry Avalanche Course (4 days)
  • This is serious country – not a place to consider unless you’re confident in the skills of your group.
  • If you are uncertain, hiring a professional NZMGA qualified guide is recommended.

The Department of Conservation has rated many tracks with the ATES scale. Click here for the Aoraki/MtCook example of ATES rated tracks


Avalanche Forecast Regions:
Mountain Safety Council managed websites
Mountainf Safety Council websiteAdventure Smart websiteNew Zealand Avalanche Center

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