Abstract
Introduction
Backcountry skiers and snowboarders are increasingly using avalanche airbags to improve safety. New safety devices can cause risk compensation, the concept in which users take more risks given the larger safety margin provided by the device. This may limit overall benefits. We sought to elucidate attitudes toward risk-taking behaviors and risk compensation in backcountry users relating to avalanche airbags.
Methods
A convenience sample of 144 backcountry skiers and snowboarders was surveyed after a backcountry tour in the Wasatch Mountains of Utah and the Tetons of Wyoming during the winter 2020–21 season. Demographic and experiential data were compared with risk propensity scores and attitudes toward risk compensation. Respondents were stratified into high-, medium-, and low-risk groupings based on risk propensity scores and whether an airbag was carried.
Results
Thirty-two (22%) respondents carried an airbag. Airbag users were more likely to endorse risk compensation behavior, ski terrain over 30 degrees, and fall into the high-risk cohort. The high-risk cohort was also more likely to endorse risk compensation behavior than medium- and low-risk individuals.
Conclusions
Risk compensation was more prevalent in 2 groups: 1) those carrying an airbag and 2) those falling within the high-risk cohort. Given the prevalence of avalanche airbags, risk compensation should be considered alongside other human factors in avalanche safety and education so that users can mitigate these effects. Although risk compensation appears to be occurring, the magnitude of this effect remains unknown and likely does not obviate the safety benefits of the airbag altogether.
Introduction
Avalanche airbags are the only avalanche safety devices that can prevent burial for an individual caught in an avalanche. After their original development in the 1980s, these devices have seen increasing commercial production and adoption by the backcountry community since the early 2010s. These devices utilize a compressed gas cylinder or a high-speed fan to inflate the airbag from the user’s backpack. In an avalanche, the airbag functions by making the user a larger particle and therefore more likely to be sorted to the surface and less likely to be buried, known as granular convection. By preventing burial, airbags can prevent asphyxiation, which accounts for approximately 85% of deaths in those caught and buried in an avalanche. 1 Avalanche airbags have indeed been shown to be effective in reducing mortality, 2 reducing adjusted absolute mortality from 22 to 11%. 3
Although avalanche airbags are effective safety devices, users must understand their limitations in order to maximize the safety benefit. Airbags can be destroyed by tree branches or other objects. Topographic features such as terrain traps can limit the airbag’s effectiveness. Deployment failure because of mechanical malfunctioning or user errors will render the airbag useless. 2
Risk compensation is another potential limitation of avalanche airbags. 4 This concept states that individuals have a predetermined level of accepted risk and will work to maintain that level in light of changing external risks. More risk or a smaller safety margin will trigger more conservative choices and vice versa. 5 Within the backcountry environment, an individual exhibiting risk compensation behavior will accept more avalanche risk exposure in the presence of the increased safety margin provided by airbags. Similarly, an individual whose airbag is taken away can also limit themselves to more conservative terrain given their decreased safety margin. Although avalanche airbags likely induce some degree of risk compensation in the backcountry, the magnitude of this effect is not yet known. 4
Four conditions were proposed by Hedlund 6 for risk compensation to occur. Safety devices that 1) are more visible, 2) negatively impact the user’s experience, 3) allow for a reward, and 4) are utilized in a space where users have control over their actions create conditions for risk compensation. Airbags are large devices with a unique leg strap and triggering mechanism serving as constant reminders of the airbag’s presence, increasing their visibility. The increased weight of an airbag along with the requirement to refill gas canisters or charge the fan battery can negatively impact a user’s experience. The reward offered by the airbag via an increased safety margin is fresh snow and steeper lines. Finally, the backcountry environment allows users to choose where they go and what risks they take with few limitations. Airbags fulfill these conditions more so than other common avalanche safety devices, making them potential catalysts of risk compensation behavior. 6
Prior work on risk compensation and airbags has primarily relied on computer-based tools. These studies have suggested that airbag users might have a high propensity for risk-taking behaviors, and compensation behavior might occur.4,7,8 Although studies structured around computer-based surveys do offer the benefits of a more standardized set of conditions, they are inherently limited by virtue of being removed from the backcountry environment.
The purpose of this study was to assess risk behavior among backcountry users related to the avalanche airbag. We sought to determine the prevalence of risk compensation behavior among these individuals and the relationship avalanche airbags might have with such attitudes. The questionnaire was also structured to determine which groups of individuals might be the most prone to risk compensation. We aimed to answer these questions via questionnaire in a backcountry setting to overcome limitations of prior computer-based surveys on the topic.
Methods
This study was reviewed and deemed exempt by the University of Utah institutional review board. Participants were a convenience sample of skiers and snowboarders surveyed immediately after backcountry ski tours in variable weather conditions in the Wasatch Mountains outside of Salt Lake City, Utah, as well as the Tetons of Jackson, Wyoming. To address risk compensation, airbag users were asked if they would have made more conservative terrain choices had their airbag not been present; individuals who were not carrying an airbag were asked if they would have made more risky terrain choices if they had carried an airbag. Results were recorded using a 5-level Likert scale. Structured this way, any affirmative answer to these questions was taken as evidence of risk compensation for participants both with and without an airbag.
Risk propensity scores were calculated using the same 9 statements (Table 1) used by Haegeli et al. 4 Survey respondents answered these questions on a 4-level scale choosing from “Does not apply,” “Applies a little,” “Applies often,” and “Applies almost always.” A score of 1 was given to answers of “Does not apply” and 4 for answers of “Applies almost always,” and similarly for the answers in between. These scores were summed to give a risk propensity score for each respondent. The scores were categorized into tertiles between low-, moderate-, and high-risk cohorts.
Risk propensity statements 4
Demographics, safety, and risk characteristics for categorical variables were summarized as counts (%) and for continuous variables as mean (SD), median (interquartile range), and range. The median was used to summarize variables with skewed distributions. Survey responses were also stratified by whether or not an airbag was carried and by risk grouping. Differences in airbag carry status were tested using Student’s t test or exact Wilcoxon rank sum test for continuous variables and χ2 or Fisher exact test for categorical variables. Differences across risk groups were tested using a Cochran-Armitage trend test for binary variables and a χ2 or Fisher exact test for categorical variables with more than 2 levels. A Jonckheere-Terpstra test was used for continuous variables. Statistical analysis was carried out by the University of Utah Study Design and Biostatistics Center, with all analyses being performed using RStudio with R version 3.6.1.
Results
Table 2 describes demographics and backcountry use of participants. The average backcountry user was male (79%), with 13 y of backcountry experience and at least 20 outings per year (72%). A total of 32 respondents (22%) were carrying an avalanche airbag. Table 3 shows survey results broken down into avalanche airbag user and nonuser groups. No significant difference in sex, age, or formal avalanche training was observed between these 2 groups.
Descriptive statistics of survey respondents
Survey responses by airbag carried/not carried
tt test.
χ2 test.
Exact Wilcoxon rank sum test.
Fisher exact test.
When stratified by risk cohort (Table 4), the medium- and high-risk cohorts were found to skew more toward male sex than the lower-risk cohort. Survey participants who were grouped into the high-risk cohort also tended to be younger with fewer years of experience but had more outings per year. Rates of airbag usage increased within increasingly higher-risk cohorts.
Survey responses stratified by risk cohort (calculated from responses to questions in Table 1)
Risk level categories were constructed from risk score.
Cochran-Armitage test for trend.
Jonckheere-Terpstra test.
χ2 test.
Fisher exact test.
Participants were asked about reasons for not owning an airbag. Of 102 respondents who indicated that they had not bought one, 52 (51%) cited cost and 34 (33%) cited weight as barriers to ownership. In the free text option for the question, 23 (23%) indicated low-risk terrain or lack of effectiveness and 16 (16%) cited a concern that an airbag would change their decision-making as a reason for not owning one. Participants were also asked why they were not carrying an airbag if they had access to one. Twelve respondents indicated that they had access to an airbag but chose not to carry one because avalanche risk was low (75%), it was not needed (33%), it was too heavy (33%), or it was not in working order (8%).
Discussion
We found that individuals who carried airbags and those who had higher risk scores were the most likely to be at least neutral to or in agreement with risk compensation playing a role that day. Rates of risk compensation were found to be higher among individuals carrying an airbag (28%) than among those not carrying one (17%) (Table 3, P=0.08). Rates were also higher among individuals falling into the high-risk cohort (34%) than among those falling into the medium- (20%) and low-risk (4%) cohorts (Table 4, P<0.05). The actual impact of risk compensation on mortality and avalanche involvement remains unknown, but these data make the prevalence of the underlying behavior patterns as well as at-risk populations clearer.
Overall, participants had strong avalanche safety habits, with >95% reading the avalanche forecast and carrying an avalanche transceiver, probe, and shovel on every backcountry trip. Airbags were used by approximately 20% of the study population, and the usage was highest in the high-risk cohort. This result is logical, given that the high-risk cohort was also the most likely to ski slopes over 30 degrees, widely considered to be the threshold over which most avalanches occur.
The cohort with the highest risk propensity was younger and had fewer years of experience than their low- and medium-risk counterparts. This high-risk cohort also had the highest rates of airbag usage and was more likely to acknowledge that risk compensation played a role in their decision-making. This finding supports the observation by Haegeli et al 4 that the rate of avalanche involvement per year of the “Thrill Seeking” cohort increased after buying an airbag, suggesting that individuals exposed themselves to more risk once they started using an airbag.
More than half of those not carrying an airbag cited cost and one-third cited weight as reasons an airbag was not owned or used that day. A novel additional finding within this survey was the 16% of individuals who cited concern that an airbag would alter their decision-making as a reason to forego an airbag. Choosing not to use a safety device with a proven mortality benefit would be akin to foregoing a seatbelt in the car or a helmet on a bike ride in order to ensure more conservative behaviors.
Additionally, 13 respondents reported that they had access to an airbag but chose not to carry it due to low avalanche risk. This implies that if the avalanche risk was higher, they would have either carried an airbag or found more conservative terrain. Risk compensation will be minimized if airbags are used as a regular part of the user’s everyday avalanche safety kit. This would decrease the conspicuity of the airbag within the risk perception and decision-making framework. If an airbag plays a role in decision-making on each outing, particularly if the decision to carry one is dependent on avalanche risk, then conditions are ripe for risk compensation to occur. Although an airbag does weigh more than a transceiver and thus can negatively impact a trip, every respondent who indicated that they chose not to carry one due to low avalanche risk also indicated that they carried their transceiver, probe, and shovel on every outing. The decision to carry a transceiver, shovel, and probe was independent of the degree of avalanche risk, whereas the decision to carry an airbag apparently was. Airbags have the ability to improve mortality for those caught in an avalanche. A risk-dependent attitude toward airbags seems to be an important inconsistency unique to airbags.
Limitations
Multiple trailheads were surveyed across a wide geographic area in varying conditions, and a wide range of terrain was accessible from each trailhead. However, selection bias could have taken place with respect to different user populations at any given trailhead. The retrospective nature of the questions also introduces susceptibility to recall bias.
Conclusions
Individuals carrying an avalanche airbag were more likely to endorse risk compensation than noncarriers. Risk compensation was also more prevalent among individuals with high-risk propensity than among low- and medium-risk counterparts. Risk compensation remains an important potential limiting factor of the safety benefit of avalanche airbags. However, the magnitude of this effect is still unknown. This phenomenon could be taught in avalanche safety courses and be included in airbag user manuals, allowing airbags to be used in a way that maximizes safety and efficacy. Although risk compensation likely occurs, concerns over its effects appear to be a barrier for some to own or use an airbag. Avalanche airbag use should be encouraged, and dedicated education should inform users of possible risk compensation to maximize safety benefit.
Footnotes
Acknowledgements
Author Contributions: study concept and design (JL, SM); data acquisition (JL); drafting and critical revision (JL, SM); approval of final manuscript (JL, SM).
Financial/Material Support: This project was facilitated in part through funding from the University of Utah Department of Emergency Medicine.
Disclosures: None.