Whether you’re hiking, snowshoeing, or cross-country skiing through the mountains, avalanches are not to be regarded lightly. We’ve all seen enough video clips and movies to know that they are a force to be reckoned with and one to be avoided at all costs. Even in situations where you played by all the rules and did everything you were supposed to, Mother Nature still sometimes throws a curveball and you might find yourself on a remote snow-covered mountain that’s showing the signs of an avalanche. Here is some information on what exactly you’re up against as well as how to properly prepare yourself.
What Triggers an Avalanche?An avalanche occurs once the weight of the snow is too much and the snowpack fails and collapses under the pressure. It’s hard to determine what the strength of a snowpack will be since the snow grains vary depending on size, density, temperature, airflow, received sunlight, difference in terrain, and more. A lot of avalanches occur naturally either during a storm or when the snowpack changes, such as by partially melting, but can also be triggered by exploring visitors. There are three different types of avalanches to look out for: slab, powder snow, and wet snow.
Slab AvalancheA slab avalanche occurs when covered layers of weakened snow fracture and collapse. They mostly happen during and up to 24 hours after a storm that leaves 12 inches or more of fresh powder. This new snow overloads the existing layers and creates a break. These avalanches can be huge chunks of snowpack, sometimes spanning an entire mountainside, and typically carry downslope for a long time with the possibility of reaching up to 80 mph. Approximately 90% of avalanche-related deaths are due to slab avalanches—many who find themselves involved in a slab avalanche will rarely escape alive.
Powder Snow AvalanchesPowder snow avalanches occur with fresh, dry powder and essentially become a snow cloud. These are the largest avalanches to form out of turbulent suspension currents. Typically these avalanches are able to move along flat surfaces for long distances and only make up a small amount of injuries or deaths comparatively.
Wet Snow AvalanchesAlthough wet snow avalanches move slowly, they can take up a large amount of space, can result in serious injury, and end up being pretty destructive leaving trees, boulders, and most of what they come into contact with in their wake. They occur from a loose snow release in snow packs that have a lot of water saturation and are close to melting point. A lot of times these avalanches occur toward the end of winter as the snow is warmed by the longer daytime hours.
How to Prepare for AvalanchesWhen going on a wintertime adventure on a snowy mountaintop, it’s best to be prepared for even the most extreme situations. Always check avalanche forecasts with park headquarters before heading out for a trip. At the bare minimum, you should bring a shovel, beacon, and probe with you. Beacons (or avalanche transceivers) are important because they can receive signals from other devices to help locate buried victims. A probe is used to dive into the snow and find a buried victim and works especially well when coupled with a beacon. Avalanche airbags and Avalungs are fantastic items that make it so a buried person has a higher chance of surviving and being rescued.
Sometimes even the most diligent and prepared hiker, skier, or snowboarder will hear the terrifying creaks that signify an avalanche. The first thing you’ll want to do is get off the breaking slab as quickly as possible by moving to the side. Snowmobilers are sometimes able to crank the speed and outrace a broken slab. If unable to escape the mass of traveling snow, try to grab onto a sturdy object such as a tree or rock instead. Humans are denser than other debris and will sink faster in the snowpack. Once the snow settles, it refreezes and makes it nearly impossible to move. Throwing a hand above the snowpack and making room in front of your face are the most important things to do if you find yourself trapped. Some claim that spitting will help you determine which way is up or that swimming will get you away from a traveling snowpack quicker, but there is no proof that either actually works. The longer a victim is submerged under the snow, the less chance they have of surviving the incident (usually being buried for more than 15 minutes leads to hypothermia and a lower chance of survival).
Hopefully, this article gave you some new information and makes you feel a bit more prepared for any winter journeys you may be planning. Download our Pocket Ranger® mobile apps to find a park to explore near you!