Avalanche safety

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Avalanches are probably the most serious and deadly danger faced on VOC trips. Avalanches kill about 10 people every year in Western Canada.

Contents

Why you need avalanche training

  • In about 87% of avalanche fatalities, a member of the victim's party triggered the avalanche. It's not a matter of luck.
  • For complete burial, survival rates are highly dependent on a quick rescue. Only members of the victim's party, with appropriate equipment and training, have a reasonable chance of getting the victim out alive. Mountain rescue and ski patrol are for body recovery only.
  • Nothing replaces face-to-face, hands-on avalanche safety training, but the CAC has put together an Online Course

Canadian Avalanche Centre Bulletins

There are two levels of avalanche information bulletins published by the Canadian Avalanche Centre (CAC). The Backcountry Avalanche Advisory is the most basic level, intended for people with no avalanche training. The Public Avalanche Forecast is next level of information, intended for people with basic avalanche training such as the Avalanche Safety Training (a two day course, previously called "Recreational Avalanche Course"). The Public Avalanche Forecast contains a danger rating and a discussion of snowpack, weather and travel conditions. Avalanche bulletins are available by telephone by calling 1-800-667-1105.

The Public Avalanche Forecast can be used together with the CAA's Avaluator tool to provide trip planning and slope analysis guidance.

Backcountry Avalanche Advisory Danger Ratings

Avalanche Conditions Travel Advice Guidance for Amateur Recreation
Avalanche good.gif
Good
Normal Caution Avalanches are infrequent but possible.
Appropriate conditions for informed backcountry travel.
Avalanche serious.gif
Serious
Extra Caution Avalanches will occur with human and other triggers.
Avalanche training and experience are essential for safe backcountry travel.
Avalanche poor.gif
Poor
Not Recommended Avalanches are occurring frequently.
Inappropriate conditions for backcountry travel without extensive avalanche training and experience.
Avalanche variable.gif
Variable
Extra Caution Conditions change from good with frozen snow to poor with melted snow.
Avalanche training and experience are essential to monitor conditions for safe travel.

International Danger Ratings

These danger ratings are used in the CAC Public Avalanche Forecast

Danger Level
and Color
Probability and Trigger Recommended Action
Low Natural avalanches very unlikely.
Human triggered avalanches unlikely.
Travel is generally safe. Normal caution advised.
Moderate Natural avalanches unlikely.
Human triggered avalanches possible.
Use caution in steeper terrain on certain aspects.
Considerable Natural avalanches possible.
Human triggered avalanches probable.
Be increasingly cautious in steeper terrain.
High Natural and human triggered avalanches likely. Travel in avalanche terrain is not recommended.
Extreme Widespread natural or human triggered avalanches certain. Travel in avalanche terrain should be avoided
and confined to low angle terrain,
well away from avalanche path runouts.

Terrain Ratings

Avalanche Terrain Exposure Scale (ATES) v.1/04

Description Class Terrain Criteria
Simple 1 Exposure to long angle or primarily forested terrain.
Some forest openings may involve the runout zones of infrequent avalanches.
Many options to reduce or eliminate exposure. No glacier travel.
Challenging 2 Exposure to well defined avalanche paths, starting zones or terrain traps;
options exist to reduce or eliminate exposure with careful routefinding.
Glacier travel is straightforward but crevasse hazard may exist.
Complex 3 Exposure to multiple overlapping avalanche paths or large expanses of steep, open terrain;
multiple avalanche starting zones or terrain traps below;
minial options to reduce exposure.
Complicated glacier travel with extensive crevasse bands or icefalls.

The detailed technical criteria for Simple, Challenging and Complex ratings are available from the Parks Canada website

Avalanche Safety Equipment

The most important piece of safety equipment is your brain. Use it. Always make a concious effort to evaluate risks before committing to any slope.

Essential Personal Gear

These are the things that are considered essential when traveling in avalanche terrain. Every member of a party should carry them.

Avalanche Transceiver
Avalanche Transceivers let rescuers locate buried avalanche victims. Everyone in a part should be equipped with a transceiver. Modern transceivers send and recieve at 457kHz, and are not compatible with older 2275 Hz transceivers. The only thing a 2275 Hz transceiver should be used for is your dog. All transceivers are designed to use only non-rechargeable alkaline batteries. The reason for this is that these batteres have a gradual predictable discharge curve, and the transceiver can detect that the battery is running low long before it is dead. Rechargeable and Lithium batteries on the other hand tend to die rather suddenly, so there is very little time from the fist appearance of a low battery warning to when the transceiver stops working completely.
Avalanche Probe
A collapsible probe for finding a buried avalanche victim. On average, having a probe and a transceiver reduces rescue time by several minutes compared to a transceiver alone. This speed improvement can be critical for the survival of a victim. Probes are also used to located victims who are not wearing transceivers by systematically probing the avalanche deposit zone. Locating victims by this method takes many hours and live recoveries are very rare. Probes are also useful for measuring snowpack depth and probing for crevasses. Some probes have a ruler inscribed on them so they can be used to measure snowpack layers when doing a snow profile.
Shovel
For digging of course. Hopefully you only ever have to use it to dig pits for snow profiles, snow caves, or a snow kitchen.

Optional Personal Gear

These safety items have not yet been widely adopted by backcountry skiers. However they may increase avalanche survivability considerably.

Avalung
If in place prior to burial, the mouthpiece of the AvaLung reduces likelihood of an ice mask forming around the face and causing asphyxiation. It functions as an artificial air pocket through which air is taken from the surrounding snowpack. See the manufacturer's website for more info.
Avalanche Airbag
The role of the avalanche airbag is to keep you on the surface in case of a running avalanche. It prevents you from getting buried under the snow mass. It prevents complete burial. ABS Systems makes these.
RECCO Reflector diodes
The RECCO system puts both the transmitter and reciever (called the detector) into the hands of the rescuer. The resucer looks for reflections off special reflector diodes that are attached to the victim. The diodes are very inexpensive compared to avalanche transcievers, but the RECCO detectors are big, heavy and expensive, and thus are usually only owned by rescue agencies. Realistically, the RECCO system can only help you if you get into an avalanche situation a short distance away from a rescue agency that owns a RECCO detector, and you are able to alert the resuce agency and they are able to get to you by helicopter quickly. In BC some, but not all, ski areas and search and rescue agencies have RECCO detectors including Whistler-Blackcomb, Cypress Mountain, Grouse Mountain [1]

Optional Group Gear

Having some of these in the group is a good idea, especially in marginal terrain and conditions. This equipment, when used properly, can help you make the right descisions to avoid getting involved in an avalanche, so you won't need to use your fancy rescue equipment.

Snow saw
saws are handy for doing snowpack tests like the compression test or shovel shear test. Some saws will attatch to a probe or a ski pole and allow you to cut out a large isolated column for a Rutchblock test.
Avaluator
The Avaluator is a new descision making tool from the Canadian Avalanche Centre. One side is used for trip planning with respect to terrain ratings and the forecast hazard. The other side is used for slope stability decisions. It has 7 questions that can help to identify high risk avalanche conditions.
Ruler
For measuring layer thickness when doing snowpack analysis. Inscribed avalanche probes also work well.
Loupe & crystal screen
For examining snow crystal structures
Inclinometer
Steeper slopes are more prone to avalanching. An inclinometer is a device for precisely measuring slope angle to help with risk assessment. Some compasses have a built in inclinometer.

Field Observations

A professionally taught avalanche course can teach you how to make observations in the field to assess avalanche risk.

External Links

Avalanche prevention and rescue training materials

Beacon Reviews website

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