Best Strategies for Surviving
Snow Avalanche Disasters.



Surviving Snow Avalanche Disasters is Possible with the Right Knowledge and Equipment.

Surviving snow avalanche disasters consisting of large masses of snow requires special knowledge and equipment. But, as with many things in nature, you don't have the opportunity to control many of the factors to ensure a successful outcome. The best you can do is to mediate and improve the odds for you personally. Your survival outcome isn't always predictable or positive. The best survival strategy is not to get into a snow avalanche situation by knowing what causes them in the first place and when you are aware that the conditions for a snow avalance exist--stay out of the area.

Simply defined, snow avalanches occur when a large mass of snow slides down a mountain side. But, how they are formed and what causes them is more complicated. However, not all snow avalanches are dangerous. Below is a picture of a modest example after it concluded. (However, one similiar to this one killed two skiers in 2007 in the same location.)

Snow Avalanche in Elderberry Canyon on Mt. Tom, 3/11/2004, Steve Burnham Photo

A Snow Avalanche Video

Alta Snow Avalanche

Avalanches can be surprising, sublimely beautiful but also very deadly! The information given here is not a guarantee that you will be able to survive a given snow avalanche disaster regardless of how much equipment or how well you execute your survival training. The information you gain here will, however, greatly improve your survival chances and limit the extent of your injuries. Surviving avalanche disasters depends on many factors, most of which you cannot control when such a situation occurs and you find yourself swept up in such an avalanche.

Snow avalanches are an awesome spectacles to observe from a safe distance but they are horrifying to be caught in one. They can sweep trains off their tracks, crush buildings, uproot trees and bury people. Some avalanches have even covered entire houses with people still inside them. And, even though movies and news reports say that they "strike without warning," most deadly avalanches start when victims trigger them.

To understand how avalanches form, you need to understand the properties of snow crystals. Depending on the temperature, humidity and other atmospheric conditions, snow crystals can have a variety of shapes, but all are generally hexagonal or six-pointed. For an excellent analysis visit the following website for more details and pictures:

How Stuff Works:http://science.howstuffworks.com/avalanche.htm

To better survive avalanche disasters it is helpful to understand the basic elements of a snow avalanche. Snow avalanches have three primary ingredients -- snow, a sloped surface and a trigger. A weak layer within the snowpack, caused by ice surfaces, depth hoar, faceted crystals, or graupel also contributes to the process. If the weak layer is near the surface, it causes a sluff -- a cascade of loose, powdery snow in an inverted "V" shape down the slide of the mountain. Sluffs are like sand rolling down a dune, and they usually cause minimal damage to people and property.

If the weak layer is deeper in the snowpack, it can cause a slab avalanche, which is far more dangerous to survive. In a slab avalanche, a strong, cohesive layer of the snowpack slides down over a bed layer of snow, like thawing snow sliding down a car's windshield. Sometimes, the entire snowpack breaks free from the mountain and slides over the ground.

Snow avalanches are a serious danger for winter sport enthusiasts. ­­­­So what do you do if you're caught in a snow avalanche? How can you stay alive, and what does it take to rescue people who've been buried in the snow?

Feasibility of Snow Avalanche Occurrence in Your Area

Generally, snow avalanches of the more dangerous type occur in the higher mountain areas where greater quantities of snow pack can accumulate. Typically ski areas or high mountain towns are most at risk or along certain mountain highways. So, to be at risk you generally need to take yourself into the area by skiing, mountain climbing, snowmobile or living in a risk area. There are websites that inform interested parties of the potential dangers of avalanches as well as fatalities.

Surviving Snow Avalanche Disasters by Understanding Snow Avalanche Environments and Triggers

Not all snow avalanches are the same. What you do depends upon the type and scale of the avalanche. They only become disasters when they destroy life and property. Surviving avalanche disasters then often depends upon people being wise enough to stay out of the areas that are ripe with conditions. Secondly, if people find themselves in an area of risk, take precautions not to trigger and event. And, lastly, if people find themselves in one, they will hopefully manage their survival with the presence of proper tools and actions.

Types of Snow Avalanches

  • Loose Snow Avalanches : These start from a single point incorporating more and more unconsolidated snow as they fan out. They are caused when the weight of new fallen snow succumbs to the forces of gravity. This occurs most often after periods of heavy snow (10-12 inches accumulation, or snowfall of one inch or more per hour), especially when piled on top of a smooth snow surface (from thawing, freezing, or rain). The smooth snow surface provides a slick ramp for the heavy new snow to run down.

  • Slab Avalanches : Are caused when well-compacted and cohesive layers of snow aren't anchored to the slope. If there is a weak layer of snow underneath the compacted layer, the slope is primed to avalanche. Various forces -- sun, wind, or a person -- can trigger the slab at the release zone.

  • Snow Avalanche Sites : Open slopes between 25 and 45 degrees, especially lee slopes (the direction toward which the wind is blowing), which get greater snow loads.

Surviving Snow Avalanche Disasters by Proper Planning and Preparation

Snow Avalanche Safety--What to Take

Snow Avalanche Safety Video

  1. Most victims trigger their own avalanche.

  2. Be aware of your surroundings. Watch for evidence of sliding, snow sluffs (small slides indicating avalanche danger), avalanche chutes or slides where trees have been torn away, or snow debris at the bottom of a slope indicating previous avalanches.

  3. Keep track of the weather. The first 24 hours after a heavy snow, high wind, rain, or thaw is the most dangerous period. Check local avalanche forecasts and be prepared to postpone your trip if the danger is high. Delaying for 24-48 hours can significantly reduce the danger.

  4. Recognize danger zones and be conservative about planning your route or crossing a slope.

  5. Travel on ridge tops or heavily wooded areas as much as possible.

  6. Avoid the mid-slopes or the release zone near the top of the slope.

  7. Detour completely around a suspect slope.

  8. If you must cross an avalanche slope, gather as much information as you can about the snowpack. Probe the snow to see if there is even resistance (if so the danger may be reduced). If there is uneven resistance to the probe breaks through a crust, punches into layers of loose or unconsolidated snow) then the avalanche danger may be high. Even better, find a safe location on an adjacent slope with similar exposure, snow level and steepness and dig a test pit. Look at the different layers. If you see layers characterized by course, grainy crystals, the slope is probably not safe. If layers are firm and bonded it might be safe.

Crossing Avalanche Zones

  1. Remove ski pole straps and undo all pack buckles.

  2. Put on additional warm clothing in case of entrapment.

  3. Zip on and fasten all clothing securely to keep snow from entering (cuffs, collars, etc.)

  4. Use avalanche cords or an avalanche beacon.

  5. Look at the crossing. Are there any islands of safety along the way, a rock outcropping, a stretch of trees? If so, head to the island of safety as soon as possible if a slide is triggered.

  6. Cross one at a time with all other group members watching.

Surviving Snow Avalanche Disasters--The Actions to Take During a Snow Avalanche

Self-Rescue

  1. Yell to alert the group.

  2. Jettison your pack and head to an island of safety if possible. Otherwise, try to stay on top of the snow using a swimming motion.

  3. If you are on a snowmobile, get away from the machine if it doesn’t appear that you can out run the avalanche. Staying near hit could injure you seriously.

  4. Before the snow stops, try to make an air pocket in front of your face by punching out the snow with your hands. Take a deep breath to expand your chest before the snow settles. The snow will quickly set like concrete. If your chest is not expanded, you may not be able to breathe.

Group Rescue

  1. Watch the victim in the slide. Where was the person when they were first hit by the slide (point A) and where were they when you last saw them (point B)?

  2. Mark point A and B on the slope with visible objects.

Actions to Take After Surviving a Snow Avalanche Disaster.

Most sources say that a person who is completely buried can live for about 18 minutes. Even though snow is porous and contains a lot of trapped oxygen, victims breathe their exhaled air, causing carbon dioxide poisoning. Warm breath also melts the snow, and it can re-freeze as a solid, non-porous layer of ice that oxygen cannot easily penetrate. With sizeable air pocket that is open to the outside, you can avoid suffocation, but you still run the risk of hypothermia and shock.

Self-Rescue

  1. Try to reach your hand to the surface to provide a clue for rescuers (if you can tell where the surface is).

  2. If possible, try to dig yourself out.

Group Rescue

  1. Visualize the line between point A and B. This is the path the victim was swept down. Look for any clues on the surface (clothing, skis, etc.) that might give more indication of the person's position. Mark these spots.

  2. Turn your avalanche beacons to receive and begin search procedures.

  3. Probe the snow below point B. Stand shoulder to shoulder and advance down slope in a line.

  4. If you locate the victim, dig him out quickly.

  5. Treat for hypothermia and shock.

  6. There is a good chance of head and spinal injuries in an avalanche as well as fractures. Be careful moving the person. Survivors are often very bruised.

Additional Resources for Surviving Snow Avalanche Disasters

If snow avalanches are a constant danger where you live or the sports you engage in, consideration should be given to receiving specialized survival training and equipment. There are a number of website sources offering this type of training.

Also, there exists specialized equipment to carry with you if you are doing sporting activities in potential areas of snow avalanche risk.

In addition to probes, transceivers and shovels, some people use high-tech safety gear to improve their chances surviving avalanche disasters. One device, called the AvaLung, lowers the likelihood of suffocation. It pulls air from the snowpack through a mouthpiece. When you exhale, it diverts the carbon dioxide-rich air to the snow behind you so you don't re-inhale it.

In any system of moving particles, large particles tend to stay on top while smaller particles filter to the bottom. Inflatable airbags and vests increase a person's size relative to the particles of snow and debris around them, so they tend to stay closer to the top of the flowing avalanche. The airbags also provide additional buoyancy and may protect against physical trauma from the moving debris. Two airbag systems currently available are the ABS avalanche airbag and the Avagear avalanche life jacket.

The following sources provide some additional information on surviving avalanche disasters created by snow.

1. The information is taken from the Outdoor Action website, located at: www.princeton.edu/~oa/index.shtml.

2. Mono County Sheriff Search and Rescue http://www.monosar.org/article20001109avalanche.html

3. A comprehensive website about avalanches is found at www.avalanche.org.

Historical Notes for Surviving Snow Avalanche Disasters:

Credits:

The following sites were some of the contributing sources for surviving snow avalanche disasters in snow.

Mono County Sheriff Search and Rescue: http://www.monosar.org/

How Stuff Works:

http://science.howstuffworks.com/avalanche.htm

Links:

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