Put simply, avalanches are a whole lotta snow and debris falling downhill under gravity with great kinetic power and can vary wildly in size, speed and terrain. Rocks, trees, chunks of earth and even animals and man made structures can all be carried under the unrelenting force and power of avalanches. As you explore ski resorts and mountainous backcountry seeking its pristine beauty and fun, educating yourself on avalanche fundamentals is a critical step to ensure your safety.
What Causes an Avalanche?
An avalanche is a mass of snow, ice, and rocks falling rapidly down a mountainside. Snow, gravity, slope and kinetic energies cause avalanches. The lower the slope, the lower the risk and the steeper the slope, the higher the risk. Slopes as low as 25-30 degrees can create avalanche risk while slopes between 30-45 degrees, which are steep enough to collect snow without being so steep that snow immediately slides off and the most prone. Avalanche risk assessment considers various factors beyond just angle of slope, including snowpack stability, weather conditions, and terrain features.
Snowfall, wind transport, temperature changes, instability and terrain features are the biggest influencers on avalanche formation. The depth/volume of snowpack and its speed impact not only its potential formation, but also its potential harm to wildlife, the environment, humans, and man-made structures. The type of snow present and the temperature fluctuations it goes through can cause the instability avalanches thrive on. The weight of an overlying snowpack eventually breaks loose at a point of failure within the snowpack or the ground surface itself, usually in planar fashion. Risk assessment includes not only present weather conditions, but seasonally and historically as well.
Human activity can also trigger avalanches, and the presence of people and structures increases potential harm. Human activities can be the kinetic catalyst causing avalanches to slide. Sometimes this is intentional intervention (controlled explosions), and other times it’s accidental through activities like skiing, snowboarding, snowmobiling, climbing, construction/development and even walking on unstable slopes. Understanding and mitigating risks through education, proper planning, and adherence to safety protocols are essential for reducing the likelihood of avalanche accidents, human caused and otherwise.
Are Avalanches Predictable?
Avalanches are complex phenomena influenced by a combination of factors. While some aspects of avalanches can be planned for, predicting the exact timing and location of avalanches is never guaranteed. Depending on prediction alone would be dangerously haphazard. As a result, avalanche risk is mitigated, not cured. Predictable variables include identifying terrain, local/regional snowpack conditions, and past/present weather patterns prone to avalanche formation, which are arguably still not 100% predictable among a non-static planet.
Assessing avalanche risk is a dynamic strategy full of ever-changing variables and prone to human and natural failure. Assessing risk does not guarantee predicting risk. Forecasting centers use various tools and techniques to assess avalanche risk and provide warnings to the public, with mixed success. They rely on historical data and knowledge of local terrain combined with hard data and real field observations to make informed predictions you might call “areas of concern”. In high risk areas, avalanche territory will be avoided entirely and/or intentionally triggered to prevent unexpected slides. This is common practice in mountainous ski resorts around the world.
While avalanche forecasting provides valuable information for risk assessment and decision-making, it's essential for individuals traveling in avalanche terrain to first prepare through education (like AIARE classes). Once in avalanche territory, it’s important to remain vigilant, continuously assess conditions, and always be prepared to adjust your plans accordingly. It’s also important to have the right gear for ascent and descent, including key pieces for saving yourself and also saving others.
Avalanche Education: Experiential guided workshops, Avalanche Skills Training (AST), AIARE Avalanche Education Classes, etc.
Good Planning: Routes, weather, community experience, historical data, avalanche forecasts, expert guides, and clear exit/emergency plans combined with other hard data available before entering risk territories.
Avalanche Transceiver (Beacon): Used for finding someone buried and being found if buried yourself.
Probe: A collapsible pole 8-10 feet long and sturdy enough to penetrate hardpack (260-300cm)
Shovel: Sturdy enough for shoveling heavy snow and debris for extended periods of time.
Airbag Packs: Commercially available backpacks equipped with airbag systems designed to help prevent/lessen potential burial of wearers.
Gear: Appropriate attire, navigation (compass/map/GPS), two-way radios/sat-phones and first aid kit, survival equipment
Before you head out for your next winter mountain adventure, take part in hands-on training through one of our AIARE Classes. Our courses are designed around a typical workday schedule in order to maximize learning time and everyday life, with 3 three-hour zoom lectures and two full-day field days in Rocky Mountain National Park. We practice how to read snow, use gear and save lives. Give us a call at 720-242-9828 or contact us to learn more.
Comments