Below, Don Carpenter reviews the AM Form that he completed for the tour in the Teton area.
We hope you enjoyed this activity. The exercises are meant to prepare you for a trip into a lodge in the future.
During the course, you will be expected to take weather station observations. This is a skill that you will be tested on towards the end of the course. Here is an explanation of the observations you will be tested on.
Before heading out into the backcountry, it is important to ask, “Is the weather contributing to instability?” The weather can directly contribute to instability with new snow, strong winds, and/or warming temperatures.
Tracking the weather throughout the season can highlight additional ways that the weather may contribute to instability over a longer time period. Weak layers, such as facets and surface hoar, can be formed during periods of cold, clear, and calm weather. These weak layers become problematic when they are buried.
A season long view of the weather history can help to pick out trends. Season histories can also be very useful if headed into a new area.
Here is a video discussion weather factors to pay attention to, as well as information on why we track season history.
When looking at if a particular slab, weak layer, bed surface is likely to produce an avalanche, the third component that we look at is friction.
We focus on the friction created between the slab, the disrupted weak layer and the bed surface and if that residual friction can be overcome to produce an avalanche.
Watch the following video to learn more about friction.
The fourth component of the stability wheel is strength. In snowpits, we measure strength by the number of taps that initiate failure in our stability tests. Strength is influenced by many things, including rapid loading, rapid warming, and time.
Watch the following video on strength.
It is important to study the relationship between the slab, the weak layer and the bed surface. Consider the structure, the propagation potential, the residual friction, the strength, and the continuity of the structure across a slope or mountain range.
Trying to sort through all of this data can be overwhelming at times. Remember, class 1 data trumps everything. If you are witnessing avalanches or experiencing cracking or collapsing, that is mother nature screaming in your ear.
The stability wheel is one way that we think about avalanche mechanics and avalanche release. The four components of the stability wheel include: structure, propagation, friction and strength.
The first component that we are going to talk about is structure. When thinking about structure, we ask, “Is there a path of least resistance?” We quantify this path of least resistance by using the Lemons or 5 components of structure.
Let’s talk about structure:
Another important component of avalanche mechanics is propagation. In order for an avalanche to occur, the slab, weak layer, bed surface combination needs to be able to sustain propagation.
While we can’t evaluate an entire slope, we can dig pits to look for propagation. What we are looking for in stability tests is if the slab, weak layer, bed surface combination can sustain propagation. We use the extended column test, as well as the propagation saw test to look for propagation.
Let’s dig into propagation in this video:
The third and fourth components of the stability wheel can be found on the next page.
When thinking about avalanche release and mechanics, it’s important to return to the foundational question – is there a recipe for an avalanche?
In the following videos, we are going to discuss avalanche release and the components involved in avalanche release. What happens when an avalanche releases is:
- Initiation of a failure and fracture. 2. Propagation of this fracture. 3. Fracture of the slab. 4. The overcoming of friction
It is important to be prepared to spend the night out and/or to evacuate an injured partner from the mountains. Some injuries or situations need a lot of resources to support. Carry a communications device so that you can contact Search and Rescue if a situation in the backcountry arises and you need back up.
At times, you might need to move your partner a short distance or you might need to get them out of the mountains. Keep in mind that any injury or illness in the backcountry takes a lot of time, energy, and resources to manage. Here are a few thoughts about evacuating someone from the backcountry.
If you or your partner is caught and carried in an avalanche, it is possible that you are hurt. It is important to be prepared to manage injuries in the backcountry. Here are some thoughts on backcountry first aid following an avalanche.
We recommend taking a Wilderness First Aid or Wilderness First Responder class, if you’re planning to spend a lot of time in the backcountry.
You can find a checklist for what to include in a first aid and repair kit here.
There are many facets of a well-executed avalanche rescue. Practicing all of the components is essential, as buried victims have the best chance of survival if they are recovered within the first 10 minutes.
Watch this video from Backcountry Access about organizing an avalanche rescue.