Risk treatment is the step following assessment and forecasting. It is how one plans to alter any of the factors contributing to the risk by changing the hazard or the vulnerability or exposure of the element at risk.
Fundamental to our efforts in avalanche risk management is to reduce our vulnerability by providing the opportunity to find and recover someone who has been buried. We do this through using and practicing with companion rescue equipment and ensuring there is a rescue party that is not exposed to the avalanche potential. We also need to be able to mount a search and rescue within the limited time of expected survival.
In treating the hazard, consider which component is being addressed; what can you do to change the problem, its likelihood, or its size?
Snow Avalanche Risk Management Framework and Mitigation Graphic. Adapted from Technical Aspects of Snow Avalanche Risk Management─Resources and Guidelines for Avalanche Practitioners in Canada (C. Campbell, S. Conger, B. Gould, P. Haegeli, B.Jamieson, & G. Statham Eds.). Revelstoke, BC, Canada: Canadian Avalanche Association 2016.
When talking about mitigation strategies at large, we want to distinguish between short-term and long-term measures, as well as direct and indirect measures.
Direct measures are actions taken by the organization which directly affect one of the avalanche risk factors- hazard, exposure, or vulnerability. Explosive mitigation, road and terrain closures, and construction of avalanche deflection berms are all direct measures. Indirect measures are policy and planning measures intended to create a safer environment but do not directly affect the avalanche risk factors. When considering the temporal scale, short-term measures are temporary, and executed over hours or days. Examples include explosive mitigation, terrain use guidelines based on level of training, and personnel equipment requirements. Long-term refers to measures that occur over several years and are more or less permanent like zoning for structures, the physical location of a roadway, deflection berms, reinforced buildings, and snowsheds (TASARM 2016).
Using transportation corridors as an example, policies like having plow drivers wear beacons and report any avalanches to the road, avalanche warning signs, and the avalanche forecast itself are all examples of short-term indirect measures. The actual physical location of a road corridor to limit the interaction with avalanche paths would be a long-term indirect measure. Using explosives to produce smaller avalanches more frequently above an affected stretch of highway would be a short-term direct measure. Placing a series of retarding mounds between the path and the highway would be a long-term direct measure.
For field operations, the short-term measures employed are of principal interest. A snowmobile guide working in avalanche terrain will rely on indirect measures such as policies that dictate the level of training required to enter different classifications of terrain, and what gear she will be required to carry. Exposure control such as employing a zone list with the coding of Open or Closed, as well and implementing sound group management are direct measures.
Ski area personnel assigned to avalanche reduction work will be reliant on indirect policy and procedure such as the type of explosive ordinance they are permitted to use, carry or, deploy and the type of personal protective equipment required to participate in their workplace environment. An avalanche transceiver, probe and shovel are all industry standard, but increasingly, ski areas are equipping route personnel with air bags to reduce vulnerability in the event of an involvement. The individual’s ability to artificially trigger an avalanche using their approved ordinance, performing a slope cut, or in some circumstances mechanical compaction of a weak layer starting in the early season are all examples of direct measures employed by field operators.
An organization’s risk treatment will fall in line with its operational risk band. Even after mitigation efforts have been employed to reduce the risk to as low as reasonably possible, some risk remains. This residual risk cannot be eliminated and organizations and their field operators will decide to take action, or not, knowing that some uncertainty will always remain. The possibility of a low-frequency event, such as a historic avalanche cycle destroying a lift terminal, is acceptable for a ski area knowing that this is extremely rare and that other short and long-term measures will be employed to reduce the likelihood. However, a backcountry guiding operation cannot accept the risk of a low-frequency event such as this impacting a yurt where overnight guests and guides are sleeping.
105mm Howitzer used for long-distance explosive mitigation efforts at a ski area or highway.
Photo: Sean Zimmerman-Wall
Avalauncher used for medium-distance explosive mitigation efforts at a ski area.
Photo: Jay Dash
Hand charge used for short-distance explosive mitigation efforts at a ski area.
Photo: Sean Zimmerman-Wall
Guide instituting group management to reduce exposure to only one person at a time.
Photo: C/O Duncan Lee
The guide's track is on the right. It is placed as a visual indicator or "fence" to keep clients away from more hazardous areas.
Photo: Sean Zimmerman-Wall
Avalanche fencing used at a ski area to break up the slab in the starting zone above a lift terminal.
Photo: Sean Zimmerman-Wall
Avalanche fences used at a ski area to break up the slab in the starting zones above the piste. Co-located with a RACS.
Photo: Sean Zimmerman-Wall
Snow shed designed to carry flowing debris over the highway in the track of an avalanche path.
Photo: Sean Zimmerman-Wall
An avalanche airbag policy for patrollers on route as part of a Snow Safety Plan is aimed at reducing vulnerability. While the tool is a direct measure, the implementation of a policy during the planning phase is indirect.
Photo: Eric Anderson
AMGA Scope Of Practice specifies the level of training related to terrain use for AMGA members and employees of AMGA accredited businesses.
SOP Cover Page. Adapted from Scope of Practice By American Mountain Guides Association. Retrieved 20210921 from https://amga.com/wp-content/uploads/2021/10/SOP_9_21_21_Revised.pdf
Yurt placement along a ridgeline to eliminate exposure to avalanche hazard.
Photo: Sean Zimmerman-Wall
Aerial tramway alignment to reduce exposure to avalanche paths.
Photo: Sean Zimmerman-Wall
Highway alignment to reduce exposure to avalanche paths.
Photo: AIARE Files