Avalanche Safety & Snowmobiling

Eric Peterson

Avalanches that involve snowmobiles do not randomly happen. In most Avalanche incidents the victim or another party member triggers the slide. This tells us that these unfortunate happenings are preventable. If we choose to ride in Avalanche terrain we are taking on inherent risks whether we realize it or not. Education is the most powerful tool that we can use to ride safely in Avalanche terrain. Through education and training you can gain the knowledge and skills required to evaluate the Avalanche hazard and weigh the risks. Riding in Avalanche terrain without the proper education, training and equipment is like playing Russian roulette! Do you feel lucky?
Most of the Avalanches that occur in our Maritime snowpack happen during or immediately following precipitation or wind activity. Our snowpack tends to be deeper and stronger than the Intermountain (Idaho) and Continental (Colorado) snowpacks. The strength of our snowpack can be a double edged sword though. Our snowpack’s strength comes from its well bonded dense snow. This cohesive dense snow also makes for very dangerous hard slab Avalanches. Avalanches are also known as the “Great White Dragon”. If you use this analogy, our “Dragons” tend to sleep more but when they awake and unleash their power they can lay a path of destruction that’s hard to comprehend.
There are four key factors that need to be considered when evaluating the Avalanche hazard.

1 Terrain
2 Snowpack
3 Weather
4 Human

If the terrain is not steep enough for Avalanches to occur then there is no risk to worry about. Slope angle is the most important element of Avalanche terrain. Avalanches can occur on slopes with angles from 25 to 60 degrees but most often happen from 35 to 45 degrees. The prime slope angle for Avalanches to happen is 38 degrees. Another important factor to consider is the consequences of being swept by a slide. Even a very small Avalanche can be deadly if it takes you off a cliff or runs you into a tree.
In regards to the snowpack we need to ask ourselves the question “could the snow slide?” This can be a very complicated question to answer even with years of Avalanche experience. The winter snowpack is made up of layers of snow that represent the different precipitation events, temperature changes and wind events throughout the winter. Our goal is to test and evaluate the strength between these layers of snow to answer the question of stability the best we can. An obvious clue to a present instability is observing a natural Avalanche. If you see that an Avalanche has occurred it is safe to say that a slope with a similar aspect (north, south, etc…) and elevation will probably slide as well.
It has been said that weather is the architect of all Avalanches. Weather can affects the critical balance between strength and stress within the snowpack. Avalanches can occur as a result from weather from weeks or even months before. Often the snowpack can not adjust to the added stress of precipitation, extreme temperature changes or wind loading. The result can be a failure of the bonds between the layers within the snowpack causing an Avalanche.
Without the human factor there is no Avalanche hazard, if we are not in the way of Avalanches how can there be a risk? This is good in theory but fails in practice because we want to and will continue to ride in Avalanche terrain. The key to riding safely in Avalanche terrain is to know which slopes are the safest and to be able to perform a rescue. We all make mistakes and if one is made evaluating the stability of the snowpack we better be able to perform and efficient rescue. One of the basic rules of traveling in Avalanche terrain is to expose only one rider at a time. If everybody is on the slope that Avalanches who will do the rescuing?
Riding in Avalanche terrain without a transceiver, shovel and probe is like riding without a helmet or driving without a seat belt, it is just plain foolish! A transceiver is a radio beacon that can transmit and receive radio signals. In the case of an Avalanche burial they allow you to find your buddy very quickly. That is if you practice! Just because you carry the right rescue equipment does not mean you are being safe. If you do not practice using your transceiver you may cost your friend his or her life.
Here are some statistics to think about.

1 - 63% of Snowmobile Avalanche accidents occur while highmarking. (It is very common for these Avalanches to be triggered by a partner that is attempting to help a stuck highmarker. Remember one rider at a time. Do not go help a stuck highmarker!!)

2 - Since 1997 69 snowmobilers have been killed in Avalanches.

3 - Most of these fatalities happened in Montana, Alaska, Colorado and Idaho.

4 - Oregon has not had a snowmobile Avalanche accident that resulted in a fatality.*This means we have been lucky not safe.

5 - 25% of Avalanche fatalities are due to traumatic injuries.

6 - You have a 90% chance of surviving if you’re dug out within 15 minutes.

7 - At 30 minutes you only have a 40% chance of surviving.

8 - 64% of the survivors are rescued by their partners. You are the rescue team!

9 - If a rescue team has to be brought in you only have a 20% chance of surviving.

10 - Rescue doesn’t work that well. From 1950 to 1999, 682 rescues have been performed and only 292 survived. That is only a 43% survival rate, if you get caught, buried and need rescue you don’t even have a 50/50 chance!

To sum all this up, we need to educate ourselves about Avalanches if we are going to ride in or near Avalanche terrain. We need to carry the appropriate rescue equipment (transceiver, shovel and probe) and know how to use them. Having basic first aid skills can mean the difference between life and death. We need to ride with an open mind and open eyes so that we see the clues that nature gives us. If we choose not to do these things we are needlessly gambling with our lives and the lives of our friends.
Eric Peterson has gained his Avalanche experience from being a ski patroller at Mt. Ashland for 10 years and teaching Avalanche safety and rescue. Eric is an avid rider and enjoys the backcountry on his Ski-Doo Summit 800 as often as he can. He is currently teaching Avalanche safety through Oregon Rescue Technologies of Medford, OR.  Thank you for reading and safe riding to you!
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