How avalanches form and what to do if you find yourself in one

Key Concepts

• Avalanche: A rapid flow of snow down a sloping land surface.
• Avalanche Danger Rating: An assessment of the likelihood and severity of avalanches in a given area.
• Slope Angle: The steepness of a slope, crucial for avalanche formation (35-45° is considered ideal).
• Snowpack: The accumulated layers of snow, with a weak base layer being a significant risk factor.
• Avalanche Safety Gear: Beacon, shovel, and probe – essential equipment for backcountry travel.

Avalanche Fatalities and Geographic Risk

As reported by the National Avalanche Center, there have been four avalanche-related fatalities in the United States this year, occurring in Wyoming, Washington State, and the California Sierra Nevada. While the annual average is between 25 and 30 deaths during the winter season, the current year’s activity is concerning. The areas most susceptible to avalanches are concentrated in the western United States, specifically the mountainous regions including the Rockies (Colorado, Wyoming, Montana), the Sierras (California), and the Cascades (Washington and Oregon). These regions share common characteristics: elevations ranging from 11,000 to over 14,000 feet, steep slopes, and rapidly changing weather patterns.

Avalanche Formation: The Three Key Ingredients

Avalanche formation requires three primary ingredients. First, a high-risk slope with an angle between 35 and 45 degrees is necessary. This angle provides sufficient gravitational pull to initiate snow movement while still allowing for snow accumulation. Second, uneven snow distribution due to wind loading creates varying snow densities – light snow in some areas and heavy, compacted snow in others. Third, rapidly changing weather conditions, particularly warming temperatures following significant snowfall, destabilize the snowpack.

This year, a particularly weak base layer of snow, resulting from a slow start to the snow season, combined with a more active storm pattern and heavier snowfall, is creating a “perfect recipe” for avalanches. The lack of a robust base layer means that subsequent snowfall is more likely to trigger slides.

Early Warning Signs of Avalanche Risk

Several early warning signs indicate increased avalanche risk. Obvious fresh avalanche activity on nearby slopes is a primary indicator and should prompt immediate avoidance of the area. Other warning signs include visible cracks forming in the snowpack and rapidly warming temperatures. These conditions suggest instability within the snowpack and an increased likelihood of an avalanche.

Survival Strategies if Caught in an Avalanche

If caught in an avalanche, attempting to outrun it is generally ineffective. The recommended strategy is to move sideways to attempt to escape the main flow. If unable to move to the side and becoming buried, the priority is to shed any heavy gear that could weigh you down. Crucially, individuals should attempt to create an air pocket around their face. Digging out while buried is counterproductive, as the surrounding snow will compress further, hindering escape.

As stated by CBS News Colorado meteorologist Joe Rook, “if you try to dig out, think about it, the snow will actually compress onto you. That's the worst case scenario.”

Preventative Measures and Essential Equipment

The most effective preventative measure is to avoid avalanche terrain when the avalanche danger is elevated. For those venturing into the backcountry despite warnings, carrying essential avalanche safety gear is paramount. This includes an avalanche beacon (transceiver), a shovel, and a probe.

Joe Rook emphasized, “carry a beacon, a shovel, and a probe if you're traveling across the back country.” These tools are critical for locating and rescuing individuals buried in an avalanche.

Logical Connections & Synthesis

The video establishes a clear connection between weather patterns, snowpack conditions, and avalanche risk. It begins by highlighting the current fatality statistics and then systematically explains the factors contributing to avalanche formation. The progression from identifying risk areas to understanding warning signs and survival strategies provides a logical framework for avalanche awareness. The emphasis on preventative measures and essential equipment underscores the importance of preparedness when engaging in backcountry activities.

The main takeaway is that avalanches are a serious hazard in mountainous regions, and understanding the contributing factors, recognizing warning signs, and carrying appropriate safety equipment are crucial for minimizing risk and maximizing chances of survival.