Every year, thousands of skiers, climbers, snowmobilers, drivers, and others worldwide are caught in avalanches. While most are fortunate enough to survive, more than 150 people each year lose their lives, and those numbers have been steadily increasing over recent decades.
Even small avalanches can be life threatening, but the good news is that, contrary to Hollywood representations, avalanches very rarely plummet onto the heads of unsuspecting victims with no advance warning. Ninety-five percent of avalanche victims are caught in slides triggered either by themselves or a companion. That means that, with proper care, most avalanche casualties can be prevented.
Even in those rare cases of drivers, mountain dwellers, and others caught in the path of a naturally occurring avalanche, careful attention to weather conditions and warnings could often have made the difference between being in the path of a slide or not. Paying attention to avalanche warnings before travel is of particular importance.
Simply put, an avalanche is a fast-moving flow of snow sliding down a mountainside. Worldwide, as many as 1,000,000 natural avalanches occur each year. The largest North American avalanches can release up to 300,000 cubic yards of snow — enough to fill the equivalent of 20 football fields with snow to a depth of 10 feet. Most natural avalanches occur in remote locations, unobserved by human beings, with only a tiny percentage threatening life or property.
Many factors contribute to avalanches. The greatest risk of avalanche exists on slopes steeper than 25 degrees or flatter than 60 degrees; that’s because snow rarely accumulates steep slopes, and doesn’t flow easily down relatively flat slopes. Because few people carry protractors with them, a good rule of thumb is to remember that any slope flat enough to hold snow but steep enough to ski has the potential to produce an avalanche.
Weather factors also play an important role, though the ways temperature and precipitation affect snowpack are complex. Avalanches are most likely to occur during or immediately after a heavy snowstorm. Until it has a chance to bond with the pre-existing surface layer, recent snowfall puts extra stress on the existing snowpack.
Long-lasting temperature increases that cause snowmelt can also seriously weaken the bond between upper layers of snow, contributing to a greater likelihood of avalanche. On the other hand, temperatures that consistently stay well below freezing can prevent snow layers from bonding together, increasing their instability. Rainfall between snows can create a slick surface on the existing top layer, making it difficult for new snow to bond.
So, how can you increase your chances of survival if you are caught in an avalanche? The most important thing to remember is never to travel in the mountains alone. If you do become buried, your greatest chance for rescue comes from nearby companions who witness the run and, hopefully, take notice of your relative location.
If an avalanche does sweep down on you, yell to get companions’ attention and make swimming motions in an attempt to thrust yourself toward the surface of the snow. Once the motion of an avalanche ends, the snow can set as hard as cement, making it almost impossible to dig yourself out. You have only a few seconds to punch out an air pocket in front of your face to prevent suffocation. Immediately take a deep breath to expand you chest, otherwise the hardened snow could constrict your breathing. If possible, try to push an arm or a leg to the surface to help rescuers spot you. And, perhaps hardest of all, do not panic. Maintaining a steady, slow breathing pattern will conserve energy and maximize your breathing pocket.
If you manage to escape the avalanche, but someone you’re with goes under, remember that it’s crucial to begin looking immediately. Statistics suggest that survival chances decrease drastically for anyone buried longer than 30 minutes. Try to keep sight of the victim as they are carried down the slope, and note where you lose sight of them. Wait a minute or two after the snow settles before carefully moving toward the spot where you last saw the victim. Start by looking for clues on the surface of where they may have gone under, such as hands, feet, or pieces of clothing. Pay particular attention to trees or large rocks in the area where they may have become lodged. Once found, administer first aid, rescue breathing or CPR as necessary and try to get them somewhere warm.
Did you know?
Avalanches cannot be triggered by shouting or other sounds. The force exerted by the pressure in sound waves not intense enough start an avalanche.
If you’re traveling in an area prone to avalanches, be sure to check what the danger level is before setting out. Here’s a quick breakdown of the North American Avalanche Danger Scale:
Green: Low risk
Snowpack is generally stable.
Only isolated areas of instability.
Backcountry travel is fairly safe.
Natural or human-triggered avalanches unlikely.
Yellow: Moderate risk
Some areas of instability.
Natural avalanches unlikely; human-triggered avalanches possible.
Backcountry travel possible with caution.
Orange: Considerable risk
Unstable areas probable.
Natural avalanches possible; human-triggered avalanches probable.
Backcountry travel possible with extreme caution.
Red: High risk
Unstable areas highly likely on various slopes and aspects.
Natural and human-triggered avalanches highly likely.
Backcountry travelers should avoid steep slopes and wind-loaded slopes.
Black: Extreme risk
Extremely unstable layers in snowpack.
Natural and human-triggered avalanches are certain.
Large destructive avalanches probable.
Backcountry travelers should avoid any steeply angled terrain or known avalanche areas.