Here is a copy of the checklist to use as we go through planning a tour.
Start by looking at this avalanche forecast:
What jumps out at you? What elevations do you want to avoid? What aspects? What slope angles?
Watch this video to go through a tour plan with AAI instructor, Sarah Carpenter
How do we use the forecast and observations to put a plan together?
It is important to have a system for planning and executing a day in the backcountry.
The AAI Backcountry Checklist provides a framework for this. The Pre-trip Plan is completed before you leave for the mountains. This section helps you identify terrain appropriate for the conditions and terrain that is off limits for the day.
The Identify Avalanche Terrain section is what should take place in the field. The goal is to prompt a continuous, focused conversation when you are approaching and moving through avalanche terrain.
The goal of the Post Trip Discussion is to continue the conversation from the mountains and to help facilitate learning. If you ask these questions each day, it can improve communication between you and your partners and provide opportunities for continuing education.
Weather is a big player in the world of snow and avalanches. Specific to winter weather, we pay attention to:
AAI instructor, Jenna Malone, talks through the weather variables in this presentation, as well as thresholds that raise a red flag.
Snow behaves differently in different conditions. It is a material that is both temperature sensitive and rate sensitive.
In the following talk, Don Sharaf discusses why snow is like silly putty. He also talks about forces that strengthen and weaken a snowpack.
Understanding likely trigger points can be helpful in terrain selection in the backcountry. Some likely trigger spots are listed below.
Let’s talk more about how snow behaves.
How do you assess snow stability? What should you be looking for while out on a tour? Here are some thoughts on informal stability tests.
Sometimes informal stability tests aren’t enough, and you want to dig in the snow. Here is some information about snow pits and formal stability tests. We will spend time in the field using both informal and formal stability tests to assess the snowpack
There is a lot of information that one can gather on a tour. How do you sort and prioritize what you are seeing in the backcountry? Here are a few thoughts.
When thinking about snowpack, the primary question to ask is: Do we have a recipe for an avalanche?
The recipe for an avalanche consists of a SLAB, a WEAK LAYER, a BED SURFACE, and TERRAIN steep enough to slide.
Don Sharaf introduces the recipe for an avalanche and how snow metamorphism plays a part in this in the following video.
What forms a slab?
One process that forms slabs is rounding. Rounding is a strengthening process that happens at small temperature gradients.
Watch the following video to learn more about rounds, as well as other processes that form slabs.
What forms a weak layer?
One process that forms a weak layer is faceting. Faceting occurs when a large temperature gradient exists.
Let’s take a deeper dive into weak layer formation and what processes develop common weak layers.
The final component for the recipe for an avalanche is the bed surface? What processes form bed surfaces? How do you recognize them? Watch this final video to learn more.
Route planning starts long before you head out on a tour. Here are a few tips as you begin route planning.
Route finding in and around avalanche terrain is an important skill. Knowing how to measure runout angles is a useful skill to help you determine if you are in an avalanche path or out of the runout zone.
In rare cases of wet slab avalanches or slush avalanches, these rules of thumb for alpha angle may not apply. These avalanches might run further.
Downloadable apps for measuring runout angles include:
https://wbskiing.com/inclinometer.php
https://play.google.com/store/apps/details?id=com.glidelinesystems.dioptra&hl=en_US
Knowing how to measure slope angles is important for avalanche terrain identification. Here are a couple ways to measure slope angles.
Recognizing avalanche terrain is an essential skill. As you spend more time in the backcountry, this terrain recognition will help you to navigate a variety of conditions throughout the winter.
If there is ever a question on a backcountry day – a question about snowpack, a question about weather, strange group dynamics – terrain is the answer. We say this because you can control your exposure to avalanche hazard through terrain choice. There are days when you may choose to avoid avalanche terrain and days when you feel confident traveling in avalanche terrain.
Most slab avalanches occur on terrain that is between 30°-45°. Measuring slope angle is one thing that you can do as a backcountry traveler.
Other terrain features that are important to recognize are terrain traps. A terrain trap is any feature that increases the consequences of getting caught in an avalanche.
The basic understanding of avalanche terrain is a skill we hope to build in this lecture and in the field portion of your course. Let’s talk through essentials of terrain.
Now that you have a foundation for recognizing avalanche terrain, let’s talk about how you move through that terrain. What should you consider when you’re route finding going uphill, as well as when you are going downhill. We will discuss a few facets of backcountry travel techniques.
Here is a brief introduction of the Colorado Avalanche Information Center Website. The CAIC covers the entire state of Colorado, breaking the state up into zones with specific forecasts.
The goal of this video is to highlight the information available on this website, as well as where to find this information.
