This is an extremely important step in the Daily Process and not one that can be fully explored here. Ahead are some critical points. To learn more, do one of our Avalanche Skills AST1 courses (starting mid July when there should be enough snow!)
We know there are many hazards in the backcountry and avalanche danger is but one. There are more incidents in the Australian backcountry due to surface conditions than avalanches, and some of the worst are a combination of under-estimating the conditions, over-estimating your ability to deal with them, and human behaviours (mental biases that cause flawed decision-making).
Evaluating slopes for surface condition hazards such as ice and breakable crusts can be predicted to a point by watching the weather, especially temps, looking at slope aspects, and putting the two together. Often it is a matter of timing with conditions changing through the day due to temps and solar.
Mountain Sports Collective mountainsportscollective.org reports on backcountry conditions such as surface conditions, wind and precipitation throughout the Australian season.
For reducing avalanche risk, evaluating and understanding the significance of the following factors can minimise the likelihood or consequences of triggering an avalanche. The importance of being able to rapidly assess terrain for its avalanche risk cannot be overstated as staying safe in the backcountry is all about selecting appropriate terrain for the conditions.
Slope Angle As long as there is no exposure from above, you can effectively lower avalanche risk by choosing low angled slopes – less than 30 degrees.
Slope Size The larger the slope the larger the potential slide.
Slope Shape Avalanches initiate more frequently from convex slopes. Concave slopes and planar slopes are generally safer but if sufficiently steep may still avalanche.
Orientation to Wind Slopes lee to wind can become loaded during strong wind events and develop wind slabs. Cross loading of slopes is also a major concern and learning to identify these conditions is essential as these slopes often present as the best riding.
Orientation to the sun In Australia north facing slopes are our solar aspects. On days with sunshine or high thin cloud the sun’s rays can be your friend or your foe. They may soften icy slopes after a melt freeze cycle on the one hand but on the other add weight to the snowpack and significantly increase avalanche danger as seen last year in the Etheridge Ridge slide.
Supported or unsupported slopes A sufficiently dense treed slope (tight to ski through) can lower avalanche risk. Convex roll features are an example of an unsupported slope and avoiding these will lower the risk.
Terrain traps Avoid areas where terrain traps such as cliffs,creeks, gullies and benches would increase the consequences of an avalanche.
If an avalanche forecast is available (it must be provided by a qualified avalanche forecaster), you can select areas where more favourable conditions exist – for example, a west-facing line in the alpine could be a good choice if a wind slab problem is listed on east aspects.
Snow profiles and snowpack tests can evaluate the state of the snowpack. The use of these tests by recreational users can be problematic due to the difficulty of selecting safe, representative test sites and because there is significant potential for making a false assessment. Professionals are trained to use snowpack tests to rule terrain out as opposed to ruling it in. If there is any question of avalanche hazard, a better option is to choose safer terrain as described above.
It is important to use good travel habits regardless of the conditions. That way these strategies become routine behaviours or habits and will protect you from surprise events. Used diligently, they reduce the likelihood of getting caught out and minimise the severity of the situation, whether it be an avalanche or other backcountry hazards.
GOOD COMMUNICATION: Keep open lines of communication and involve all members in decision making. Many groups use two-way radios to stay in contact.
ONE AT A TIME: Wherever possible, expose only one person at a time to avalanche terrain. In big terrain, be strategic about spreading out to reduce the potential consequences of an avalanche.
GROUP UP IN SAFE SPOTS: Group up out of avalanche terrain but also keep in mind your position for a potential rescue. If you descend too far or out of view, you may not see an incident and it could take a long time to climb back up if a rescue is required.
PLAN AN ESCAPE ROUTE: When in avalanche terrain, plan an escape route before you commit to a slope.
USE TERRAIN WISELY: Exploit terrain features to your advantage. Utilise high ground, such as ridges and ribs rather than being sucked into gullies. Maintain situational awareness of the terrain, including what is above and below you.
ACTIVELY LOOK FOR INSTABILITIES: Do stability tests regularly as you travel. Jump on small rolls and slopes with little to no consequence, do hand shear and compression tests, to see if you can get the snow to fail.
Five minutes can be a long time in the Australian backcountry. Most forecasts for weather, snow conditions and avalanche hazard cover a wide geographical area. It is common for conditions to vary from one part of the region to another. Regional variabilities and uncertainties in forecasts make verifying the conditions an important step in your daily process. The aim is to determine whether the conditions are different than expected and if so, make appropriate changes to your plan. These changes may range from aborting the trip to adjusting the plan to a lower risk option with greater emphasis on slope evaluation and maintaining good travel habits.
It is good to verify the conditions before leaving the trailhead, however unexpected hazards often only become apparent during travel, in which case modifying the plan to take these changes into account is a must. You may find few options are available and that you are already exposed to the hazard. Communication amongst your group becomes all-important and is key to implementing a change or retreat.
Factors which can affect your plan include the amount of new snow, temperature, wind loading, visibility, snow conditions, snowpack instability, avalanche occurrences. As you travel, keep observing and evaluating, and communicating your thoughts to the others in your group. Stay alert and open to changing the day’s plan. No plan should ever be set in concrete in the backcountry!
NEXT WEEK: STEP 5 USE GOOD TRAVEL HABITS