Stay Safe in Avalanche Country

Sure, speeding down well-groomed ski runs can be fun, but if you like your wilderness wild, the resort scene may not be your cup of cocoa. Out in the back country, there are no crowds or high-priced lift tickets, but there are plenty of majestic views and wondrous solitude. Unfortunately, the winter mountains are also home to one of nature's most violent and deadly phenomena: avalanches. Knowledge, preparation, and caution are the keys to survival in avalanche country.

Steps

  1. Know the avalanche types. There are several types of avalanches possible, each dependent on the terrain, steepness, and weather:[1]
    • Loose dry-snow avalanches – These can be very large. They start at a single point and can move at 40 mph / 64.3 km/h, and at that speed can easily become airborne.
    • Airborne powder avalanches – Once airborne at a speed of around 40 mph / 64.3 km/h, these are very destructive and can reach speeds up to 175 mph / 280 km/h.
    • Slab avalanches – If a slab of snow ceases to be supported, it is easy for it to fall away. Snow accumulates on leeward slopes due to wind and unsettled snow creates soft slabs that are easily triggered by avalanche victims. Hard slabs form on lee slopes where winds are over 30 mph / 48.2 km/h and the slab turns as hard as concrete. The breaking of such a slab can be heard as a huge cracking noise.
    • Wet avalanches – These are common during Buy Boots for Spring months or following thaws, as water weakens any layers of snow, including down to the ground level. Wet avalanches can be loose or slab, fast or slow, and set like concrete once they stop making rescue time for victims extremely short. These often occur following heavy rain or a snowstorm that starts cold but ends warm.
    • Ice avalanches – Ice peels off a crag and falls down the mountainside.
    • Cornice collapse – Cornices (deposits of wind-drifted snow) can collapse under their own weight, or following a heavy snowfall.
  2. Take an avalanche safety training course and read up on avalanches. Knowledge is your best defense against the danger of avalanches, and there's no better way to gain firsthand knowledge than by taking an avalanche safety course. It is also a very good use of time to read widely on avalanche safety, as there are a number of good books devoted solely to the topic, along with many case studies that make for grim but sobering reading. It has been shown by research that most victims caught by avalanches were either unaware of avalanches or safe route travel skills, or where they did know, they chose to ignore the warning signs.[2] Taking an avalanche safety course won't dent your time much but it could save your life. Such courses vary widely in price and scope, and you can choose courses that fit your primary activities, such as skiing or snowmobiling.
    • Learn how to measure slopes both with tools and without. Learn how to recognize avalanche slopes. This includes knowing the signs of previous avalanches on vegetation and other natural features.
    • Learn how to evaluate avalanche hazards. This basically consists of asking: 1. Could the slope produce avalanches?; 2. Could the snow fail?; 3. What will happen to me if the slope avalanches?; and 4. Will conditions get worse. A good course should teach you how to respond to each of these questions and how to to a hazard evaluation summary.[3]
    • Learn how to determine wind direction. This includes noting eroded features, vegetation leans, build-up of snow, snowfall direction, rime deposits (these grow into the wind) and sastrugi.
    • Learn to ask for local knowledge, especially when you're from out of the area. It can also be helpful to look at internet records pertaining to the ski fields where you're headed, to see what previous seasons have brought by way of avalanches.
  3. Recognize nature's warning signs. The surest sign of avalanche danger is evidence of recent avalanches, an indication that local conditions are right for more. Keep in mind that 95 percent of avalanches occur during or within 24 hours of heavy rain or snowfall, and high winds also contribute to avalanche formation, so try to avoid heading off-piste in these conditions. Particularly warm days, with thawing or temperatures that approach or surpass freezing, are also high-risk. Another warning is if snow cracks, collapses, or makes a "whumph" sound beneath you; that's a sure sign that the snow is stressed and can't bear your weight. Any sudden change in temperature can trigger an avalanche. Even shadows creeping across the face of a slope can change the temperature enough to make snow unstable. If snowballs (rollerballs or sunwheels) are rolling down the slope, this is an indication of temperature increases.
    • Low temperatures prolong the chances of an avalanche risk.[4] The danger remains for at least 48 hours after snowfall and even longer when it is cold.
    • Snowfall at a rate of more than 1 inch or 2cm per hour can increase the risk of an avalanche.[4]
    • The highest danger is on slopes between 25 degrees and 45 degrees.[4] Slopes over 25 degrees tend to be sloped a fair-skilled Improve Your Cross Country Skiing Technique would avoid skiing down on skinny skis.[5]
    • Note that the convex section of snow will usually be the fracture zone for an avalanche.[4]
    • If there have been recent avalanches, heed them and do not go anywhere near where these avalanches have occurred, nor near anywhere with similar terrain and temperatures in the same locale. Watch for snow gathering on lee slopes of mountains and hills, and in wind-sheltered gullies.
  4. Pay attention to forecasts and heed professional warnings. In many mountainous areas, these forecasts are regularly updated throughout the avalanche season. You may be able to find this information on the internet, on local radio and TV, at resorts and government offices, or by calling hot lines (Colorado, for example, has 7 hot lines to cover different areas of the state). If an avalanche advisory is in effect, postpone or reroute your trip. If you're near a resort or on frequently used trails, signs warning of avalanche danger may also be present.
    • Be wary of any individual who presumes to know better than the official warnings. This could simply be a sign of foolhardiness or worse, a sign of over-confidence in their own skills and mountain knowledge. Try to reason with them but certainly don't join them if they insist on doing anything dangerous.
  5. Know how to test the snow for avalanche potential. Before venturing onto a potentially dangerous slope, find a small, safe slope close by on which you can perform stability tests. The test slope should be about the same angle and have the same aspect as the slope you want to cross, but it should be small enough so that the mini-avalanche you may trigger won't be dangerous. If you can determine that the layers of snow are well bonded and strong, the slope is probably safe. There are several tests you can perform, from stomping on the snow to digging a test pit (tests include the Swiss ski-shear test, the loaded column test, and the Rutschblock test). See the "External Links" section below for more details on precise tests. In addition, always ask yourself if the weather is contributing to the potential for instability.
    • Pick a safe trail during avalanche periods of high or extreme avalanche warnings, or stay home. Safe trails are those which do not cross over or underneath any slope steep enough to cause an avalanche.[5]
    • Don't rely on hunches, guesses and gut feelings about safety; evaluate the safety of a slope by your knowledge of avalanche potential. Ignore avalanche warnings at your own peril.
  6. Be prepared. When traveling into avalanche country, carrying some simple equipment can save your life:
    • Slope meter: Because avalanches occur almost exclusively on slopes between 25 and 50 degrees, and 90 percent of avalanches occur on slopes of 30-45 degrees, a slope meter is the single most important tool you can have to avoid avalanche danger. Use it to determine the angle of a slope before attempting to cross or climb the slope. If the angle is in the danger range, avoid the slope.
    • Rescue beacon: Wear a rescue beacon on your top layer of clothing beneath your coat. Switch in on and test it before you set out.
    • Avalanche cord: Before rescue beacons, the primary avalanche safety equipment was the rescue cord, and these are still useful. Attach one end of the cord (usually about 30 feet long) and drag the cord behind you. If you get buried in an avalanche, at least part of the cord should stay above the surface.
    • Collapsible avalanche probes. Every member of a group should carry probes to search for buried victims in the event of an avalanche.
    • Shovels: Everyone should also carry a shovel to dig out people that have been buried.
    • Avalanche Airbag System: These relatively new devices have been shown to help avalanche victims stay above the surface. You wear the system in backpack and pull a release when the avalanche starts. They're expensive (about $500-1000), but they can save your life.
  7. Practice avalanche safety while out and about. There are several key things you can do improve your chances of either avoiding or getting away from an avalanche, as follows:
    • Study the weather. If you know that the area received freezing rain, for instance, before the last snowfall the odds of an unstable slab are much higher. Learn how to recognize conditions that generate hoar frost and other avalanche promoting conditions (see how to recognize nature's warning signs above).
    • Travel in a group. If you're alone and get buried or seriously injured in an avalanche, your odds of survival are slim to none – just don't ski alone in avalanche terrain. Always travel with at least one other person, and make sure your companions are trained in avalanche safety and rescue. Try to travel with a group that is evenly matched for pace, simply because your slowest member will slow down all of you, which can be hazardous in avalanche prone terrain. If you have a slow skier in the group, reduce your ambitions for the day instead of leaving that person behind.[5] Pair up when skiing down through trees (this will help prevent problems with tree wells and tree accidents).
    • When skiing trails that cross the runout zones of avalanche paths during moderate hazard warnings, stick to traveling 50 to 100 meters apart on wide slopes, and cross narrow slopes one at a time just in case an avalanche does occur.[5]
    • Cross slopes at the top or bottom, not in the middle. If an avalanche starts when you're in the middle of a slope, you'll likely have to go too far to reach safety in time. If, however, you're near the bottom or at the very top, you may be able to quickly move out of the way or avoid danger altogether. Stick to ridgelines – but keep off cornices – or travel along valleys that give you a wide berth from the slope in case an avalanche starts above you. If you must go up or down a potentially dangerous slope, stick close to the edge and go straight up or down. Don't criss-cross the slope or travel up the middle.
    • When resting, rest well away from runout zones of potential avalanche slopes.[6] Tony Daffern in Avalanche Safety warns that while this seems like obvious advice, many a skiing family is tempted to enjoy the view from the position of the large, open snow field which also happens to be the runout zone of an avalanche slope.[6] The same advice goes for pitching your winter camp.
    • Know when to turn back. Don't push on when the going gets rough. If it's about to get dark, always turn back. And if the snowpack is unstable, turn back. You may need to exercise certain mental fortitude to convince the team to turn back, so prepare your negotiating skills and be ready to explain the signs and reasons for not wishing to press on.[7]
  8. Know what to do in the event of an avalanche. While it is hoped you will never need to have to try to escape an avalanche, knowing what to do in the event that you are caught up in one can give you a greater chance of survival. Doing an avalanche course is an important part of knowing how to react in the moments of becoming trapped in an avalanche. Learn both avalanche survival and rescue techniques. None of this is second nature; it must be learned and is not something you want to be learning for the first time in the heat of the moment.
    • Visualize your escape route. Before you even set foot on a potentially dangerous slope, scope it out to determine where you can go if an avalanche happens. Sometimes there may be isolated areas of safety, such as rock outcroppings or a stand of trees, on the slope. If not, you'll probably need to cross the slope to get to safety. Seek the quickest safe way across avalanche slopes, and have a plan before you attempt to cross them.



Tips

  • In general, north-facing slopes are most dangerous during the dead of winter (in the northern hemisphere), but south-facing slopes become dangerous in spring and during particularly warm, sunny weather. In the southern hemisphere this is reversed.
  • In a pinch, ski poles can substitute for probes, and skis or snowboards can be used as shovels. These substitutes are not nearly as effective as the real things, however, so carry probes and shovels to be safe.
  • To protect from hypothermia, wear appropriate warm clothing when crossing avalanche zones, and zip it up snugly to prevent snow from entering.
  • Avoid crossing potentially dangerous slopes if at all possible. While performing tests and taking safety precautions may save your life, the only truly safe way to travel in the back country is to avoid avalanche slopes altogether. If in doubt, don't go out.
  • While loud noises are commonly thought to trigger avalanches, research suggests that an avalanche caused by sound is highly unlikely.
  • Snowmobilers account for the majority of avalanche fatalities in North America, because snowmobiles are heavy and can cover a great deal more terrain in a day than a person on skis can. The snowmobile's ability to quickly cover distances, however, allows snowmobilers to more readily detour around avalanche slopes. If you are traveling by snowmobile, take advantage of your extra mobility and avoid danger, even if it means significantly rerouting your trip. If you're a skier near snowmobilers, pay extra attention to keeping well away from them if they're crossing avalanche prone terrain as they may trigger an avalanche.
  • High marking on snowmobiles–climbing a steep slope to compete to reach the highest point–is particularly dangerous. To be safe avoid high marking, but if you're going to do it anyway, make sure only one machine is on the slope at a time, avoid parking at the bottom of a slope, and test the slope's stability first.
  • When traveling in a group, cross dangerous slopes one-person-at-a-time. While there's safety in numbers, an avalanche can sweep the whole group away in an instant. If you must cross an avalanche-prone slope, only one person should be in danger at any given time, and the rest should watch him or her carefully.
  • Convex slopes are generally more dangerous than concave slopes, and the leeward side of mountains, where windblown snow can pile up by the ton, is usually more dangerous than the windward side. Trekking atop cornices or right below them is also a bad idea. Open, treeless slopes are danger zones, but depending on tree spacing even treed areas may have avalanche potential.

Warnings

  • Be careful when going down black slopes because it is easy to get lost or hurt and there are always minor avalanches because of the area.
  • Don't wait for professional rescuers to arrive to rescue an avalanche victim. By the time rescue crews arrive, it is usually too late to recover a victim alive.
  • Don't let down your guard or take risks simply because you have a beacon or because you're traveling with a group of well-trained companions. Even with the use of the latest rescue equipment and techniques, a large percentage of people buried by avalanches do not survive. Prevention is the key to survival.
  • Don't be stupid. All too often, peer pressure and machismo contribute to fully-preventable avalanche deaths. If you've got something to prove, an avalanche slope is not the place to do it.
  • The information in this article is a good start to keep you safe in avalanche country, but it's no substitute for an avalanche safety course.
  • A snow pit isn't a guarantee of safety, it is only a best guess. Localized conditions outside of where you dug your pit can generate avalanches. You can't dig a test pit everywhere.
  • It's a good idea to leave the beginner skiers on the beginner slopes, always. A skier who is prone to falling down will create a far bigger dent on unstable snow than a more experienced, advanced skier who skis lightly.

Things You'll Need

  • Rescue beacons
  • Shovels
  • Avalanche probes
  • Avalanche airbag
  • Slope meter

Related Articles

Sources and Citations

  1. ↑ Pete Hill and Stuart Johnston, The Mountain Skills Training Handbook, p.1109, (2000), ISBN 0-7153-1091-7
  2. ↑ Pete Hill and Stuart Johnston, The Mountain Skills Training Handbook, pp.109-110, (2000), ISBN 0-7153-1091-7
  3. ↑ Tony Daffern, Avalanche Safety, pp. 136 - 139, (2002), ISBN 0-9211102-72-0
  4. ↑ 4.0 4.1 4.2 4.3 Pete Hill and Stuart Johnston, The Mountain Skills Training Handbook, p.109, (2000), ISBN 0-7153-1091-7
  5. ↑ 5.0 5.1 5.2 5.3 Tony Daffern, Avalanche Safety, p. 19, (2002), ISBN 0-9211102-72-0
  6. ↑ 6.0 6.1 Tony Daffern, Avalanche Safety, p. 20, (2002), ISBN 0-9211102-72-0
  7. ↑ Tony Daffern, Avalanche Safety, p. 21, (2002), ISBN 0-9211102-72-0
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