Avalanches are part of life in the mountains. They can occur in any season, but are more common in winter and spring. Anytime that snow and steep slopes are combined there is potential for an avalanche.
If you travel through backcountry terrain exposed to avalanches, you must accept that you are taking a risk. You need to understand these risks before setting out.
The best way to understand the avalanche danger in the area you'll be visiting is through the New Zealand Avalanche Advisory (NZAA). The NZAA provides daily assessments of avalanche likelihood to 12 alpine regions throughout New Zealand. It provides the likelihood at different elevation bands and aspects, primary and secondary dangers, along with recent avalanche activity, current snowpack conditions and mountain weather. The NZAA is also available at DOC visitor centres.
The NZAA is provided by the Mountain Safety Council (MSC) as an advisory only. We recommend you check the mountain weather forecast as part of your trip planning.
ATES is independent of stability. The terrain class remains the same no matter what the snow stability is.
Terrain does not change with the weather. The angle and shape of the ground or the number of established avalanche paths do not vary. By using the ATES you can begin to measure your skills, experience and risk tolerance against the terrain you plan to travel in.
Description | Class | Terrain criteria |
---|---|---|
Simple | 1 | Exposure to low-angle or primarily forested terrain. Some forest or bush openings may involve the run-out zones of infrequent avalanches. Many options to reduce or eliminate exposure. No glacier travel. |
Challenging | 2 | Exposure to well defined avalanche paths, starting zones or terrain traps; options exist to reduce or eliminate exposure with careful route finding. Glacier travel is straight forward, but crevasse hazards may exist. |
Complex | 3 | Exposure to multiple, overlapping avalanche paths or large expanses of steep, open terrain; multiple avalanche starting zones and terrain traps below; minimal options to reduce exposure. Complicated glacier travel with extensive crevasse bands or icefalls. |
Reading both ATES and NZAA helps you to decide if your trip is worth the risk.
When the avalanche advisory is rated 'moderate' or above, you should select very conservative terrain. Alternatively, when the avalanche advisory is rated ‘low’, it might be appropriate to consider that next level of terrain you have been contemplating.
The two scales must be used together to appropriately manage your risk in the backcountry.
These ratings are intended as a supplement to your pre-trip planning material. 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.
If you are going into places avalanches could occur, make sure you: