Using Explosives for Avalanche Control

Avalanches are one of the most significant natural hazards in mountainous regions, with the potential to cause catastrophic loss of life, property damage and disruptions to infrastructure. To combat these dangers, ski patrol teams and avalanche specialists employ several techniques, including the use of explosives to stabilize snowpacks and prevent avalanches before they pose a threat.

The U.S. National Avalanche Center (NAC) is at the forefront of avalanche safety efforts. As a program under the U.S. Forest Service, the NAC provides leadership, technical expertise and resources for avalanche forecasting, mitigation and public education.

By supporting avalanche centers across the country, NAC ensures that regional teams are equipped to monitor and manage snow conditions effectively. Their work extends to training snow safety professionals, developing technology and collaborating on best practices for managing avalanche risks.

The role of explosives in avalanche mitigation

Explosives have been used for decades as an effective way to control avalanches. By deliberately triggering avalanches in a safe and planned manner, snow safety teams can reduce the risk of large or unpredictable events.

“There are several explosive compounds that are used for avalanche control, and one of them is TNT,” said Rebecca Hodgetts, an avalanche specialist with NAC. But there are a number of different products available. “For example, cast primers are used predominantly in Colorado and Utah and are a blend 60% [pentaerythritol tetranitrate], and the rest is TNT,” she explained.

The primary purpose of these explosives is to disrupt weak layers within the snowpack. Snowpack stability is heavily influenced by how snow accumulates and settles over time. As snow falls, it forms layers with varying densities and strengths. Some layers are weaker than others and can act as a release point for avalanches.

“The way that explosives work on the snowpack is that they create this pressure wave,” said Hodgetts. “What we are trying to do is impact these layers in the snowpack. The snowpack gets layered over time. As the snow falls during the season, each storm is slightly different as is the weather between storms. So, you get these layers or interfaces in the snowpack. Some layers are weaker or stronger than others. This relationship between weak layers of snow and the slab above it is the basics of how the avalanche phenomenon occurs. You have this sandwich of different layers which have different strengths”

Hodgetts says using explosives is one technique employed to release any weak layers with an overlying slab. “The avalanche blast will impact that weak layer and trigger an avalanche under somewhat controlled conditions, rather than releasing it naturally or from a skier trigger. So, snow safety programs are blasting ahead of the skier traffic to hopefully mitigate the avalanche risk,” she said.

Timing is a crucial factor in avalanche control. Snow safety teams must work quickly and strategically, especially at the start of the ski season, when slopes are untouched. “If they believe that that slope could produce an avalanche that’s big enough to hurt a person,” Hodgetts said, “[the snow safety team] will use explosives to try to release an avalanche, prior to even sending ski patrollers in there to ski cut or set up the slope.”

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Rebecca Hodgetts, U.S. National Avalanche Center

Effective use of explosives requires extensive training and experience. Snow safety professionals must be skilled in identifying avalanche-prone conditions, handling explosives and navigating hazardous terrain.

“Most states require some sort of certification and it takes a lot of training,” Hodgetts said. “You have to know how to use explosives safely, how to identify avalanche conditions, and how to travel in avalanche terrain without putting yourself or others in danger.”

Recent advancements in technology have also improved safety and efficiency. Remote avalanche control systems allow teams to detonate charges from a distance. “They’re remote and they have communication either by satellite, radio or cell phone,” Hodgetts said. “The charges are already on the slope and ski patrollers can detonate them from a distance. It speeds up operations and eliminates the need to put people in dangerous zones.”

Challenges in avalanche control

Despite the effectiveness of current techniques, avalanche mitigation presents numerous challenges. Developing and maintaining a snow safety plan is complex and requires co-ordination among multiple teams and organizations.

One of the biggest challenges is staffing. High living costs and the seasonal nature of the work make it difficult to recruit and retain skilled personnel. “We all know how hard it is to get to and to live in mountain towns these days. So, retention and succession of employees is a challenge,” Hodgetts said.

Communication is another critical element. Snow safety teams must ensure that all members are aligned on mission objectives and operational goals. Miscommunication in high-risk situations can lead to serious consequences. Hodgetts says it’s important for teams to assess if mission objectives were met upon return to base.

In addition, avalanche control is a highly regulated field. Ski areas must comply with federal, state and local regulations, maintain certifications and ensure that infrastructure such as remote systems and explosives storage facilities are up to code. “Certain states require you to have explosives permits and some don’t. All of them require some sort of permit, whether it’s individual or for the operation is variable between states,” Hodgetts said.

“That involves a certain amount of continuing education every year, usually eight to 16 hours of training and in certain things that you reiterate every year: How to safely handle them? How to store them? How to report problems? How do you need to keep a regular count of how many you have? You need to inspect where you store them. You need to keep all your equipment in good condition.”

A tool among many

While explosives are a cornerstone of avalanche mitigation, they are not the only method used to manage snowpack stability. Hodgetts says there are a variety of techniques to use depending on the terrain, weather conditions and specific risks.

Boot packing is one alternative used at Aspen Highlands. Teams will manually walk across unstable snow slopes to compact the snowpack and disrupt weak layers. “If you stir it all together, you hopefully diminish that layering and then you don’t have as big of a basal weak layer avalanche problem. That’s the intent,” she said.

Heavy machinery, such as snow rollers or winch cats, is also used to compact snow on slopes. These machines can stabilize large areas of terrain more efficiently than manual methods. In Europe, ski resorts often use snow structures such as nets and fences that hold the snowpack in place on steep slopes. These solutions are particularly useful in protecting infrastructure such as ski lodges, lift stations or homes in avalanche-prone areas.

However, explosives remain a key component of avalanche mitigation in many regions of North America due to their ability to cover large areas and effectively reduce risk.