Wilderness Medical Society Clinical Practice Guidelines for Prevention and Management of Avalanche and Nonavalanche Snow Burial Accidents: 2024 Update.

To provide guidance to the general public, clinicians, and avalanche professionals about best practices, the Wilderness Medical Society convened an expert panel to revise the evidence-based guidelines for the prevention, rescue, and resuscitation of avalanche and nonavalanche snow burial victims. The original panel authored the Wilderness Medical Society Practice Guidelines for Prevention and Management of Avalanche and Nonavalanche Snow Burial Accidents in 2017. A second panel was convened to update these guidelines and make recommendations based on quality of supporting evidence.

Risk of Death and Major Injury from Natural Winter Hazards in Helicopter and Snowcat Skiing in Canada.

INTRODUCTION: Guests and guides partaking in helicopter and snowcat skiing (collectively known as mechanized skiing) are exposed to numerous natural winter hazards that can result in injury or death, but detailed quantitative risk estimates are currently lacking. This lack represents a considerable barrier for evaluating existing risk management practices and implementing evidence-based improvements. METHODS: We collected historical incident and exposure information from mechanized skiing operations in Canada to perform a retrospective risk analysis. Our analysis dataset includes 713 incidents that resulted in injuries or fatalities among guests or guides during a total of 3,258,000 skier days from the 1970 to 2016 winter season. RESULTS: Overall risk of death from natural winter hazards in mechanized skiing was 18.6 fatalities per million skier days (1997-2016). Although the risk of death from avalanches decreased substantially over the entire study period, avalanches remain the largest contributor to the overall risk of death (77%), followed by tree wells and other non-avalanche-related snow immersions. The risk of death from avalanches in snowcat skiing is about half of that in helicopter skiing, but other snow immersion fatalities are more common. The risk of major injury to guests is primarily associated with other falls and collisions. The risk of major injury for guides is higher in snowcat skiing than in helicopter skiing. CONCLUSION: We recommend the design of an industry-wide incident and near-miss reporting system to support evidence-based improvements of safety practices.

Landowner preferences for wetlands conservation programs in two Southern Ontario watersheds.

Wetlands in the region of Southern Ontario, Canada have declined substantially from their historic area. Existing regulations and programs have not abated this decline. However, reversing this trend by protecting or restoring wetlands will increase the supply of important ecosystem services. In particular, these actions will contribute to moderating the impacts of extreme weather predicted to result from climate change as well as reducing phosphorous loads in Lake Erie and ensuing eutrophication. Since the majority of land in the region is privately owned, landowners can play an important role. Thus, we assessed landowner preferences for voluntary incentive-based wetlands conservation programs using separate choice experiments mailed to farm and non-farm landowners in the Grand River and Upper Thames River watersheds. Latent class models were separately estimated for the two data sets. Marginal willingness to accept, compensating surplus, and participation rates were estimated from the resulting models to gain insight into the financial compensation required by landowners and their potential participation. Many of the participating landowners appear willing to participate in wetlands conservation at reasonable cost, with more willing groups notably marked by past participation in incentive-based conservation programs. They generally favor wetlands conservation programs that divert smaller areas of land to wetlands conservation, target marginal agricultural land, use treed buffers to protect wetlands, offer technical help, and pay financial incentives. However, landowners appear reluctant to receive public recognition of their wetland conservation actions. Our results are of interest to natural resource managers designing or refining wetlands conservation programs.

Wilderness Medical Society Practice Guidelines for Prevention and Management of Avalanche and Nonavalanche Snow Burial Accidents.

To provide guidance to clinicians and avalanche professionals about best practices, the Wilderness Medical Society convened an expert panel to develop evidence-based guidelines for the prevention, rescue, and medical management of avalanche and nonavalanche snow burial victims. Recommendations are graded on the basis of quality of supporting evidence according to the classification scheme of the American College of Chest Physicians.

The effectiveness of avalanche airbags.

AIM: Asphyxia is the primary cause of death among avalanche victims. Avalanche airbags can lower mortality by directly reducing grade of burial, the single most important factor for survival. This study aims to provide an updated perspective on the effectiveness of this safety device. METHODS: A retrospective analysis of avalanche accidents involving at least one airbag user between 1994 and 2012 in Austria, Canada, France, Norway, Slovakia, Switzerland and the United States. A multivariate analysis was used to calculate adjusted absolute risk reduction and estimate the effectiveness of airbags on grade of burial and mortality. A univariate analysis was used to examine causes of non-deployment. RESULTS: Binomial linear regression models showed main effects for airbag use, avalanche size and injuries on critical burial, and for grade of burial, injuries and avalanche size on mortality. The adjusted risk of critical burial is 47% with non-inflated airbags and 20% with inflated airbags. The adjusted mortality is 44% for critically buried victims and 3% for non-critically buried victims. The adjusted absolute mortality reduction for inflated airbags is -11 percentage points (22% to 11%; 95% confidence interval: -4 to -18 percentage points) and adjusted risk ratio is 0.51 (95% confidence interval: 0.29 to 0.72). Overall non-inflation rate is 20%, 60% of which is attributed to deployment failure by the user. CONCLUSION: Although the impact on survival is smaller than previously reported, these results confirm the effectiveness of airbags. Non-deployment remains the most considerable limitation to effectiveness. Development of standardized data collection protocols is encouraged to facilitate further research.

Identifying a high-risk cohort in a complex and dynamic risk environment: out-of-bounds skiing--an example from avalanche safety.

The development of effective prevention initiatives requires a detailed understanding of the characteristics and needs of the target audience. To properly identify at-risk individuals, it is crucial to clearly delineate risky from acceptable behavior. Whereas health behavior campaigns commonly use single conditions (e.g., lack of condom use) to identify high-risk cohorts, many risk behaviors are more complex and context dependent, rendering a single condition approach inadequate. Out-of-bounds skiing, an activity associated with voluntary exposure to avalanche hazard, is an example of such a multifaceted risk-taking activity. Using a dataset from an extensive online survey on out-of-bounds skiing, we present an innovative approach for identifying at-risk individuals in complex risk environments. Based on a risk management framework, we first examine risk-taking preferences of out-of-bounds skiers with respect to exposure and preparedness--the two main dimensions of risk management--separately. Our approach builds on existing person-centered research and uses Latent Class Analysis to assign survey participants to mutually exclusive behavioral classes on these two dimensions. Discrete Choice Experiments are introduced as a useful method for examining exposure preferences in the context of variable external conditions. The two class designations are then combined using a risk matrix to assign overall risk levels to each survey participant. The present approach complements existing person-centered prevention research on the antecedents of risk-taking by offering a process-oriented method for examining behavioral patterns with respect to the activity itself. Together, the two approaches can offer a much richer perspective for informing the design of effective prevention initiatives.

Comparison of avalanche survival patterns in Canada and Switzerland.

BACKGROUND: Current recommendations for rescue and resuscitation of people buried in avalanches are based on Swiss avalanche survival data. We analyzed Canadian survival patterns and compared them with those from Switzerland. METHODS: We extracted relevant data for survivors and nonsurvivors of complete avalanche burials from Oct. 1, 1980, to Sept. 30, 2005, from Canadian and Swiss databases. We calculated survival curves for Canada with and without trauma-related deaths as well as for different outdoor activities and snow climates. We compared these curves with the Swiss survival curve. RESULTS: A total of 301 people in the Canadian database and 946 in the Swiss database met the inclusion criteria. The overall proportion of people who survived did not differ significantly between the two countries (46.2% [139/301] v. 46.9% [444/946]; p = 0.87). Significant differences were observed between the overall survival curves for the two countries (p = 0.001): compared with the Swiss curve, the Canadian curve showed a quicker drop at the early stages of burial and poorer survival associated with prolonged burial. The probability of survival fell quicker with trauma-related deaths and in denser snow climates. Poorer survival probabilities in the Canadian sample were offset by significantly quicker extrication (median duration of burial 18 minutes v. 35 minutes in the Swiss sample; p < 0.001). INTERPRETATION: Observed differences in avalanche survival curves between the Canadian and Swiss samples were associated with the prevalence of trauma and differences in snow climate. Although avoidance of avalanches remains paramount for survival, the earlier onset of asphyxia, especially in maritime snow climates, emphasizes the importance of prompt extrication, ideally within 10 minutes. Protective devices against trauma and better clinical skills in organized rescue may further improve survival.

Patterns of death among avalanche fatalities: a 21-year review.

BACKGROUND: Avalanches are a significant cause of winter recreational fatalities in mountain regions. The purpose of this study was to determine the relative contributions of trauma and asphyxia to avalanche deaths. METHODS: We reviewed all avalanche fatalities between 1984 and 2005 that had been investigated by the offices of the British Columbia Coroners Service and the Chief Medical Examiner of Alberta. In addition, we searched the database of the Canadian Avalanche Centre for fatal avalanche details. We calculated injury severity scores for all victims who underwent autopsy. RESULTS: There were 204 avalanche fatalities with mortality information over the 21-year study period. Of these, 117 victims underwent autopsy, and 87 underwent forensic external examination. Asphyxia caused 154 (75%) deaths. Trauma caused 48 (24%) deaths, with the rate of death from trauma ranging from 9% (4/44) for snowmobilers to 42% (5/12) for ice climbers. In addition, 13% (12/92) of the asphyxia victims who underwent autopsy had major trauma, defined as an injury severity score of greater than 15. Only 48% (23/48) of victims for whom trauma was the primary cause of death had been completely buried. INTERPRETATION: Asphyxia and severe trauma caused most avalanche fatalities in western Canada. The relative rates differed between snowmobilers and those engaged in other mountain activities. Our findings should guide recommendations for safety devices, safety measures and resuscitation.