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This article discusses the incidence of avalanche accidents and the usage and effectiveness of practices in prevention and safety. The authors comment on the conclusions of a recent review, stating that official statistics do not support the claim that there has been an increase in avalanche fatalities during the COVID-19 pandemic. They also highlight the variability in the rate of usage of avalanche airbags and other safety equipment, citing different studies with varying usage rates. The authors acknowledge that avalanche airbags can be effective in preventing critical burial and reducing overall mortality if used correctly, but emphasize the importance of proper maintenance and user awareness. [Extracted from the article]

Introduction: We aimed to investigate the relationship between the time of the day and the probability of survival of completely buried avalanche victims. We explored the frequency of avalanche burials occurring after sunset, and described victims' characteristics, duration of burial and rescue circumstances compared to daytime avalanches.Methods: In this retrospective, observational study, we analysed avalanche data from the registry of the Swiss Institute for Snow and Avalanche Research, from 1998 to 2020.Results: A total of 3892 avalanche victims were included in the analysis, with 72 of the accidents (1.85%) occurring in the nighttime. Nearly 50% of the victims involved in nighttime avalanche accidents were completely buried, compared to about 25% of victims in daytime avalanches. Completely buried victims were rescued by a companion less often at night than in the daytime (15% vs. 51%, p <.001). The search and rescue of completely buried avalanche victims took longer during the nighttime compared to the daytime (median 89 min vs 20 min, p =.002). The probability of survival decreased as the day progressed; it was highest at around midday (63.0%), but decreased at sunset (40.4%) and was the lowest at midnight (28.7%).Conclusions: Avalanche accidents at night are a rare event, and probability of survival after complete burial is lower during the nighttime compared to the daytime. The most relevant reason for this is the longer duration of burial, which is explained in part by the lower rate of companion rescue and the lower rate of victim localisation with an avalanche transceiver. [ABSTRACT FROM AUTHOR]

According to the living data process in ESSD, this publication presents extensions of a comprehensive hydrometeorological and glaciological data set for several research sites in the Rofental (1891-3772 m a.s.l., Ötztal Alps, Austria). Whereas the original dataset has been published in a first original version in 2018 (https://doi.org/10.5194/essd-10-151-2018), the new time series presented here originate from meteorological and snow-hydrological recordings that have been collected from 2017 to 2020. Some data sets represent continuations of time series at existing locations, others come from new installations complementing the scientific monitoring infrastructure in the research catchment. Main extensions are a fully equipped automatic weather and snow monitoring station, as well as extensive additional installations to enable continuous observation of snow cover properties. Installed at three high Alpine locations in the catchment, these include automatic measurements of snow depth, snow water equivalent, volumetric solid and liquid water content, snow density, layered snow temperature profiles, and snow surface temperature. One station is extended by a particular arrangement of two snow depth and water equivalent recording devices to observe and quantify wind-driven snow redistribution. They are installed at nearby wind-exposed and sheltered locations and are complemented by an acoustic-based snow drift sensor. The data sets represent a unique time series of high-altitude mountain snow and meteorology observations. We present three years of data for temperature, precipitation, humidity, wind speed, and radiation fluxes from three meteorological stations. The continuous snow measurements are explored by combined analyses of meteorological and snow data to show typical seasonal snow cover characteristics. The potential of the snow drift observations are demonstrated with examples of measured wind speeds, snow drift rates and redistributed snow amounts in December 2019 when a tragic avalanche accident occurred in the vicinity of the station. All new data sets are provided to the scientific community according to the Creative Commons Attribution License by means of the PANGAEA repository (https://www.pangaea.de/?q=%40ref104365). [ABSTRACT FROM AUTHOR]

Avalanches represent the primary risk of death to backcountry skiers and snowmobilers in North American and European alpine countries. The best strategy for evading dangerous snowpack conditions that may result in an avalanche event requires skiers and snowmobilers to avoid or mitigate their use of hazardous terrain. Therefore, understanding terrain use is critical to understanding the causes of avalanche accidents. Secondary, post-event examination of accident data is inadequate for this understanding, and the logistical costs of user intercept surveys are problematic. Learning more about the behaviors and practices skiers and snowmobilers use to avoid avalanche fatalities or near misses is the primary concern of the avalanche education and research community. However, the topographical data required for analysis of skier and snowmobiler behavior with respect to terrain use is beyond the capacity of most backcountry skiers to provide via traditional surveys. This paper presents the use of a novel combination of user surveys and Global Positioning System (GPS) tracking to collect detailed terrain-use data from recreationists who voluntarily engage with researchers via active participation in citizen science research projects. We describe the methodology for these observations and present why they represent an effective approach to understand avalanche accidents. [ABSTRACT FROM AUTHOR]

Objectives: More than 20 people die each year in snow avalanches in Switzerland. Previous studies have primarily described these victims, but were not population based. We investigated sociodemographic factors for avalanche mortality between 1995 and 2014 in the entire Swiss resident population. Design and methods: Within the Swiss National Cohort we ascertained avalanche deaths by anonymous data linkage with the avalanche accident database at the Swiss WSL Institute of Snow and Avalanche Research SLF. We calculated incidence rates, by dividing the number of deaths from avalanches by the number of person-years, and hazard ratios (HRs) for sociodemographic and economic characteristics using Cox proportional hazard models. Results: The data linkage yielded 250 deaths from avalanche within the SNC population for the 20 years 1995 to 2014. The median distance between the place of residence and the place of the event (avalanche) was 61.1 km. Male gender, younger age (15–45 years), Swiss nationality, living in the Alpine regions, higher education, living in the highest socioeconomic quintile of neighbourhoods, being single, and living in a household with one or more children were associated with higher avalanche mortality rates. Furthermore, for younger persons (<40 years) the hazard of dying in an avalanche between 2005 and 2014 was significantly lower than in the years 1995 to 2004 (HR = 0.56, 95%-CI: 0.36–0.85). Conclusion: Over a 20-year period in Switzerland, higher rates of dying in an avalanche were observed in men, in younger age groups, and persons with tertiary education, living in the highest socioeconomic quintile of neighbourhoods, and living in an Alpine region. For younger persons (<40 years), the hazard declined during the study period. [ABSTRACT FROM AUTHOR]

Abstract A large catastrophic rock avalanche with a total volume of ~18.0 × 106 m3 occurred at 5:38 am, 24th June 2017, at Xinmo Village, Maoxian, Sichuan, China, resulting in 102 casualties (10 deaths, 3 injuries, and 89 missing). We have been conducting a geological and geomorphological investigation in and around the Xinmo landslide site since 2015, and we present our results here, including data obtained before and after the landslide event. The landslide, which had an initial volume of 4.46 × 106 m3 of its source area, was induced by rainfall on a previous landslide scar near the ridge top. This initial landslide then struck and remobilized older landslide deposits in the middle and lower parts of the slope, which subsequently buried Xinmo Village at the landslide toe. The landslide occurred on a dip slope of Triassic calcareous psammitic and pelitic schists. The bedding plane, which dips downslope to the south with an orientation of N80°W/48°S, and high-angle NE–SW striking joints bounded the landslide source area at its base and sides, respectively. Satellite image analysis and field observations of the slope of the landslide scar before and after the landslide strongly suggest that the beds in the source area had already begun gravitationally deforming (e.g., buckling) prior to the 2017 landslide. Moreover, pits on the slip surface were likely the result of the dissolution of calcareous material. Dissolution probably reduced the rock strength along the bedding plane. A rainfall event from the 16th to 24th of June 2017 probably dominated the groundwater drainage, and finally triggered the catastrophic rock avalanche. In addition to the 2017 landslide, the hillslope just to the east of the Xinmo landslide exhibits pronounced gravitational slope deformation, including "A-tent"-like structures and warps induced by buckling. This suggests that this slope could also fail like the Xinmo rock avalanche during a future rainfall or earthquake event. Highlights • Geological and geomorphological features of the Xinmo landslide were characterized. • Geological structures generated by buckling existed prior to the landslide. • A stability evaluation indicates that the buckling preceded the landslide. • The landslide was probably induced by pore pressure buildup due to rainfall. • A slope near the landslide has been gravitationally deformed and is prepared to fail. [ABSTRACT FROM AUTHOR]

Deaths due to avalanches have a significant mortality burden in Western Canada. The aim of this review is to summarize risk factors, causes of death, and important mitigation and management strategies in treating avalanche victims. Multiple risk factors for avalanches have been identified, which relate to both physical characteristics of the avalanche environment as well as human factors. Winter backcountry recreationists should be mindful of their motivations for exposing themselves to avalanche dangers and remain objective to the physical characteristics conferring avalanche accident risk. Asphyxia is responsible for the vast majority of deaths due to avalanche, while trauma remains an important cause in certain geographic areas. Avalanche training courses educate learners on avalanche rescue sequences, which utilize avalanche transceivers, probes, and strategic shoveling techniques. The primary goal of rescue is to reduce the median time of burial, thereby decreasing the incidence of asphyxia and ultimately, death. Following the extrication of an individual from an avalanche, rescuers may have to begin resuscitation efforts. Future developments in avalanche safety should focus on public education of avalanche risk factors, incorporation of basic life support into avalanche training courses, and further development of technologies that may increase survivability. [ABSTRACT FROM AUTHOR]

An avalanche accident was occurred on 5 January 2018 on Chowkibal--Tangdhar road in Kupwara district, Jammu and Kashmir about 6 km from Chowkibal village. One light passenger vehicle was swept away in the avalanche and 10 persons lost their lives. In this communication, we study the cause of avalanche accident and simulate the snow avalanche flow using Rapid Mass MovementS model. Total snow depth recorded at the nearest observation location from the accident site was 31 cm and fresh snow of the storm was 24 cm. Avalanche condition on slope was building up and the Snow and Avalanche Study Establishment issued an avalanche warning of 'Low Danger' for the Chokibal--Tangdhar road axis. Maximum thickness of avalanche debris on road was observed to be 3.0 m. Flow simulation showed maximum velocity of avalanche to be ~25 ms-1, maximum impact pressure ~9.39 x 104 kg m-1 s-2 and maximum height of avalanche flow ~3.0 m. [ABSTRACT FROM AUTHOR]

Recent technical and strategical developments have increased the survival chances for avalanche victims. Still hundreds of people, primarily recreationists, get caught and buried by snow avalanches every year. About 100 die each year in the European Alps–and many more worldwide. Refining concepts for avalanche rescue means to optimize the procedures such that the survival chances are maximized in order to save the greatest possible number of lives. Avalanche rescue includes several parameters related to terrain, natural hazards, the people affected by the event, the rescuers, and the applied search and rescue equipment. The numerous parameters and their complex interaction make it unrealistic for a rescuer to take, in the urgency of the situation, the best possible decisions without clearly structured, easily applicable decision support systems. In order to analyse which measures lead to the best possible survival outcome in the complex environment of an avalanche accident, we present a numerical approach, namely a Monte Carlo simulation. We demonstrate the application of Monte Carlo simulations for two typical, yet tricky questions in avalanche rescue: (1) calculating how deep one should probe in the first passage of a probe line depending on search area, and (2) determining for how long resuscitation should be performed on a specific patient while others are still buried. In both cases, we demonstrate that optimized strategies can be calculated with the Monte Carlo method, provided that the necessary input data are available. Our Monte Carlo simulations also suggest that with a strict focus on the "greatest good for the greatest number", today's rescue strategies can be further optimized in the best interest of patients involved in an avalanche accident. [ABSTRACT FROM AUTHOR]

Pasquier, Mathieu, Olivier Hugli, Alexandre Kottmann, and Frank Techel. Avalanche accidents causing fatalities: are they any different in the summer? High Alt Med Biol. 18:67-72, 2017. Aims: This retrospective study investigated the epidemiology of summer avalanche accidents that occurred in Switzerland and caused at least one fatality between 1984 and 2014. Summer avalanche accidents were defined as those that occurred between June 1st and October 31st. Results: Summer avalanches caused 21 (4%) of the 482 avalanches with at least one fatality occurring during the study period, and 40 (6%) of the 655 fatalities. The number of completely buried victims per avalanche and the proportion of complete burials among trapped people were lower in summer than in winter. Nevertheless, the mean number of fatalities per avalanche was higher in summer than in winter: 1.9 ± 1.2 (standard deviation; range 1-6) versus 1.3 ± 0.9 (range 1-7; p < 0.001). Trauma was the presumed cause of death in 94% (33 of 35) in summer avalanche accidents. Sixty-five percent of fully buried were found due to visual clues at the snow surface. Conclusions: Fatal summer avalanche accidents caused a higher mean number of fatalities per avalanche than winter avalanches, and those deaths resulted mostly from trauma. Rescue teams should anticipate managing polytrauma for victims in summer avalanche accidents rather than hypothermia or asphyxia; they should be trained in prehospital trauma life support and equipped accordingly to ensure efficient patient care. [ABSTRACT FROM AUTHOR]

Following an avalanche, one of the factors that affect victims' chance of survival is the speed with which they are located and dug out. Rescue teams use techniques like trained rescue dogs and electronic transceivers to locate victims. However, the resources and time required to deploy rescue teams are major bottlenecks that decrease a victim's chance of survival. Advances in the field of Unmanned Aerial Vehicles (UAVs) have enabled the use of flying robots equipped with sensors like optical cameras to assess the damage caused by natural or manmade disasters and locate victims in the debris. In this paper, we propose assisting avalanche search and rescue (SAR) operations with UAVs fitted with vision cameras. The sequence of images of the avalanche debris captured by the UAV is processed with a pre-trained Convolutional Neural Network (CNN) to extract discriminative features. A trained linear Support Vector Machine (SVM) is integrated at the top of the CNN to detect objects of interest. Moreover, we introduce a pre-processing method to increase the detection rate and a post-processing method based on a Hidden Markov Model to improve the prediction performance of the classifier. Experimental results conducted on two different datasets at different levels of resolution show that the detection performance increases with an increase in resolution, while the computation time increases. Additionally, they also suggest that a significant decrease in processing time can be achieved thanks to the pre-processing step. [ABSTRACT FROM AUTHOR]

The aim of studies was to summarize all available published records of snow avalanche events in the Tatra Mountains in a form of a geodatabase and assess the usefulness of compiled information for analyses of long-term changes in snow avalanches characteristics. The systematic study of various sources from Poland and Slovakia resulted in geodatabase including about 3406 avalanche events, of which 2033 were registered in the Polish and 1373 in the Slovakian parts of the Tatra Mountains. The geodatabase comprises information about location, type and size of the avalanche, time of the event, source of the information as well as information about rescue missions, number of injured and fatalities. The snow avalanches causing the accidents are well documented. The rest of the avalanches were registered only as a result of the researches lasting from one up to maximum 11 winters or sporadic observations. In the Polish part of the High Tatra Mountains most of the avalanches were reported (681 events) in the Białka Valley, especially the Mięguszowieckie Szczyty ridge. In the Slovakian part of the Tatra Mountains most of the records came from the Žiarska Valley (222 events), especially the Tri kopy ridge. Although the records are unsystematic, the collected information can be used, if processed with caution, to analyse the certain aspects of the avalanche activities. The geodatabase was designed and developed in the way that allows future improvements by adding new records, either recent or historical ones. [ABSTRACT FROM AUTHOR]

Aim: To calculate the first Austrian avalanche survival curve and update a Swiss survival curve to explore survival patterns in the Alps.Methods: Avalanche accidents occurring between 2005/06 and 2012/13 in Austria and Switzerland were collected. Completely buried victims (i.e. burial of the head and chest) in open terrain with known outcome (survived or not survived) were included in the analysis. Extrication and survival curves were calculated using the Turnbull algorithm, as in previous studies.Results: 633 of the 796 completely buried victims were included (Austria n=333, Switzerland n=300). Overall survival was 56% (Austria 59%; Switzerland 52%; p=0.065). Time to extrication was shorter in Austria for victims buried ≤60min (p<0.001). The survival curves were similar and showed a rapid initial drop in survival probability and a second drop to 25-28% survival probability after burial duration of ca. 35min, where an inflection point exists and the curve levels off. In a logistic regression analysis, both duration of burial and burial depth had an independent effect on survival. Victims with an air pocket were more likely to survive, especially if buried >15min.Conclusion: The survival curves resembled those previously published and support the idea that underlying survival patterns are reproducible. The results are in accordance with current recommendations for management of avalanche victims and serve as a reminder that expedient companion rescue within a few minutes is critical for survival. An air pocket was shown to be a positive prognostic factor for survival. [ABSTRACT FROM AUTHOR]

Avalanche mitigation routinely uses explosives to both initiate avalanches and test slope stability. This project aimed to verify past findings and further develop an understanding of explosive shockwave interactions with hard and soft slab conditions within 2-5 m of the detonation. Pentolite cast boosters (0.9 and 0.45 kg) were detonated at 0.0, 0.5, 1.0, 1.5, and 2.0 m above the snow. Six orthogonally paired accelerometers inserted into the snowpack recorded snow accelerations. High-pressure sensors located at and above the snow surface measured air overpressures. Distances were scaled to trinitrotoluene (TNT) equivalents to aid in explosive placement comparisons. A substantial advantage was recorded in snow accelerations attributable to elevating explosives above the snow surface. Elevating charges not only increased overall response, but also increased the effective range and depth with no penalty in shock attenuation rates. Using attenuation relationships, a method for predicting the maximum range and affected volume for a specified acceleration value was developed. Field data showed the importance of explosive placement and how the affected volume, and thereby the probability of artificial avalanche release, can be greatly increased. [ABSTRACT FROM AUTHOR]

Avalanche accidents, particularly those resulting in fatalities, attract substantial attention from policy makers and organizations, as well as from the media and the public. Placing fatal accidents in a wider context requires long-term and robust statistics. However, avalanche accident statistics, like most other accident statistics, often rely on relatively small sample sizes, with single multi-fatality events and random effects having a potentially large influence on summary and trend statistics. Additionally, trend interpretation is challenging because statistics are generally explored at a national level, and studies vary in both the period covered and the methods. Here, we addressed these issues by combining the avalanche fatality data from the European Alps (Austria, France, Germany, Liechtenstein, Italy, Slovenia, and Switzerland) for three different periods between 1937 and 2015 and applying the same data analysis methodology. During the last four decades, about 100 people lost their lives each year in the Alps. Despite considerable inter-annual variation, this number has remained relatively constant in the last decades. However, exploring fatality numbers by the location of the victims at the time of the avalanche revealed two partly opposing trends. The number of fatalities in controlled terrain (settlements and transportation corridors) has decreased significantly since the 1970s. In contrast to this development, the number of fatalities in uncontrolled terrain (mostly recreational accidents) almost doubled between the 1960s and 1980s and has remained relatively stable since then, despite a strong increase in the number of winter backcountry recreationists. Corresponding to these trends, the proportion of fatalities in uncontrolled terrain increased from 72 to 97 %. These long-term trends were evident in most national statistics. Further, the temporal correlation between subsets of the Alpine fatality data, and between some of the national statistics, suggests that time series covering a longer period may be used as an indicator for missing years in shorter-duration datasets. Finally, statistics from countries with very few incidents should be compared to, or analysed together with, those from neighbouring countries exhibiting similar economical and structural developments and characteristics. [ABSTRACT FROM AUTHOR]

Background: Every year a substantial number of children are affected by natural disasters worldwide. However, data are scarce on long-term psychological impact of natural disasters on children's health. Identifying risk factors and outcomes associated with the long-term sequelae of posttraumatic stress disorder (PTSD) can provide a gateway to recovery as well as enhancement of preventive measures. Objective: Among childhood avalanche survivors, we aimed to investigate risk factors for PTSD symptoms and the relationship between socioeconomic status (SES) and PTSD symptoms in adulthood. Methods: Childhood survivors (aged 2-19 at the time of exposure) of two avalanches were identified through nationwide registers 16 years later. The PosttraumaticDiagnostic Scale was used to assess current PTSD symptoms. One-way ANOVA was used to explore PTSD symptoms by background and trauma-specific factors, as well as associations with current SES. Predictors of PTSD symptoms were examined by multivariable regression analysis. Results: Response rate was 66% (108/163). Results from univariate ANOVA analysis revealed that female sex was associated with PTSD symptoms (F=5.96, p<.05). When adjusted for age and sex, PTSD symptoms were associated with lower education (F=7.62, p<.001), poor financial status (F=12.21, p<.001), and unemployment and/or disability (F=3.04, p<.05). In a multivariable regression model, when adjusting for age and sex, lack of social support (t=4.22, p<.001) and traumatic reactions of caregivers (t=2.49, p<.05) in the aftermath of the disaster independently predicted PTSD 16 years post-trauma. Conclusions: Lingering PTSD symptoms after childhood exposure to a disaster may negatively influence socioeconomic development in adulthood. Strengthening children's support systems post-disaster may prevent the long-term sequelae of symptoms. [ABSTRACT FROM AUTHOR]

Rock avalanches onto glacier surfaces, involving volumes 1 Mm or more, are common in the glacier environments of NW North America. We analyse the Mount Munday rock avalanche (British Columbia) which occurred in July 1997. It involved the initial movement of 3.2 Mm of granitic gneiss that underwent a high degree of fragmentation as it was emplaced on Ice Valley Glacier as a thin 2.6-km debris sheet. The total height of the path was 850 m, and its length was 4,163 m yielding a fahrböschung of 10°, suggestive of a long runout in relation to volume. Potential energy expended in the movement was calculated as 4.33 × 10 J and its specific energy was estimated at 5,204 J/kg. A simulation of the movement using 2D DAN-W and DAN 3D strongly supports the idea that debris sheet geometry (runout and thickness) and behaviour (velocity profile) resulted from movement on a low friction surface (glacier ice). Our analysis of the debris sheet geometry of 23 unconstrained rock avalanches on glacier surfaces in NW North America indicated that the debris sheets are distinct from those in non-glacial environments in that they are (a) longer in relation to volume and (b) more extensive in area in relation to volume. These two effects result in a very thin supra-glacial debris sheet. Using image analysis software, we found that ∼85 % of the initial source rock volume was fragmented to fragment sizes less than 4.7 m in volume during emplacement, and that within the debris sheet, the highest degree of fragmentation is associated with the thinnest debris. In the emplacement of rock avalanche debris sheets on glacier surfaces, the low friction glacier surface drives debris sheet thinning through spreading, which in turn results in the fragmentation of its entire thickness. We thus propose low friction surface-driven fragmentation as a process that contributes to long runout of rock avalanches on glacier surfaces and explains their distinctive debris sheet geometry. [ABSTRACT FROM AUTHOR]

Aim Criteria to prolong resuscitation after cardiac arrest (CA) induced by complete avalanche burial are critical since profound hypothermia could be involved. We sought parameters associated with survival in a cohort of victims of complete avalanche burial. Methods Retrospective observational study of patients suffering CA on-scene after avalanche burial in the Northern French Alps between 1994 and 2013. Criteria associated with survival at discharge from the intensive care unit (ICU) were collected on scene and upon admission to Level-1 trauma center. Neurological outcome was assessed at 3 months using cerebral performance category score. Results Forty-eight patients were studied. They were buried for a median time of 43 min (25-76 min; 25-75th percentiles) and had a pre-hospital body core temperature of 28.0 °C (26.0-30.7). Eighteen patients (37.5%) had pre-hospital return of spontaneous circulation and 30 had refractory CA. Rewarming of 21 patients (43.7%) was performed using extracorporeal life support. Eight patients (16.7%) survived and were discharged from the ICU, three (6.3%) had favorable neurological outcome at 3 months. Pre-hospital parameters associated with survival were the presence of an air pocket and rescue collapse. On admission, survivors had lower serum potassium concentrations than non-survivors: 3.2 mmol/L (2.7-4.0) versus 5.6 mmol/L (4.2-8.0), respectively (P < 0.01). They also had normal values for prothrombin and activated partial thromboplastin compared to non-survivors. Conclusions Our findings indicate that survival after avalanche burial and on-scene CA is rarely associated with favorable neurological outcome. Among criteria associated with survival, normal blood coagulation on admission warrants further investigation. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Every year a large number of avalanches are triggered by anthropogenic activities. This study examines the occurrence of snow avalanches from 1940 to 2011 in the Făgăraș massif and Bâlea glacial area in the eastern region of the Southern Carpathian Mountains, Romania. We focused our attention on the relationship between anthropogenically triggered avalanches and terrain factors (including elevation, aspect and slope angle), snow depth and snow pack characteristics. We also examined the influence of issuing snow avalanche danger-level alerts to the public by the Bâlea Work Nivology Laboratory on the number of accidents since 2005. Most avalanche accidents occurred in the alpine and subalpine areas. The majority of avalanche fatalities occurred at high danger levels, while avalanche burials and injuries occurred at all danger levels (low-very high). Since the establishment of the National Administration of Meteorology and the Bâlea Work Nivology Laboratory, a marked reduction in accidents has occurred because of better education regarding avalanche hazards and the regular issuing of avalanche danger-level alerts to the public and authorities. [ABSTRACT FROM AUTHOR]

Abstract: Background: In the European Alps emergency medical helicopter services are regularly involved in avalanche rescue missions. How the helicopter emergency medical system best supports avalanche rescue missions is controversial. Aim of the study: To study advantages and limitations of the early dispatch of emergency medical helicopters after avalanche accidents. Methods: Data on rescue mission characteristics and patterns and severity of medical emergencies were obtained for 221 helicopter avalanche rescue missions performed in the Austrian province of Tyrol between October 2008 and June 2011. Results: A buried avalanche victim had to be searched for in only 12 (5.5%) of the 221 rescue missions, whereas medical emergencies were encountered at the scene in 24 missions (11%). Survival rate for totally buried victims extricated after helicopter arrival was significantly lower than for victims extricated before helicopter arrival (19% versus 74%, p =0.0002). In 124 missions (56%) no victim was present at the scene when the helicopter arrived. Medical emergencies involved normothermic cardiac arrest (n =11), severe accidental hypothermia (n =6), critical trauma (n =7) and hypothermia combined with critical trauma (n =1). Survival rate at hospital discharge was 27% for arrested normothermic patients and 50% for trauma and hypothermia patients. Conclusions: Medical emergencies are encountered at avalanche scenes twice as often as there is need to search for totally buried victims, clearly supporting the immediate dispatch of medical crew members to the accident site. The high rate of emergency medical helicopter operations to avalanche incidents where no victim is injured or buried may be characteristic for densely populated mountainous regions and can be reduced by a restrictive dispatch policy after avalanche accidents without clear information about human involvement. [Copyright &y& Elsevier]

Abstract: Background and aim: The majority of avalanche victims who sustain complete burial die within 35min due to asphyxia and injuries. After 35min, survival is possible only in the presence of a patent airway, and an accompanying air pocket around the face may improve survival. At this stage hypothermia is assumed to be an important factor for survival because rapid cooling decreases oxygen consumption; if deep hypothermia develops before cardiac arrest, hypothermia may be protective and prolong the time that cardiac arrest can be survived. The aim of the study was to investigate the combined effects of hypoxia, hypercapnia and hypothermia in a porcine model of avalanche burial. Methods: Eight piglets were anaesthetised, intubated and buried under snow, randomly assigned to an air pocket (n =5) or ambient air (n =3) group. Results: Mean cooling rates in the first 10min of burial were −19.7±4.7°Ch−1 in the air pocket group and −13.0±4.4°Ch−1 in the ambient air group (P =0.095); overall cooling rates between baseline and asystole were −4.7±1.4°Ch−1 and −4.6±0.2°Ch−1 (P =0.855), respectively. In the air pocket group cardiac output (P =0.002), arterial oxygen partial pressure (P =0.001), arterial pH (P =0.002) and time to asystole (P =0.025) were lower, while arterial carbon dioxide partial pressure (P =0.007) and serum potassium (P =0.042) were higher compared to the ambient air group. Conclusion: Our results demonstrate that hypothermia may develop in the early phase of avalanche burial and severe asphyxia may occur even in the presence of an air pocket. [Copyright &y& Elsevier]

Fatal avalanche accidents in Québec (Canada) 1825 to 2009 Archival research, coroner's investigations, and newspaper searches reveal the occurrence of 43 deadly snow avalanches in Québec since 1825. Historical records indicate 73 fatalities and more than 50 injuries. Sixty percent of the victims were younger than 20 years old. More than 50 percent of the victims (38 fatalities in 12 incidents) were inside or near a residential building, usually their home, mainly in the cities of Québec and Lévis. The second-most deadly category is recreational activities, with over 24 deaths in 20 accidents. Most of these deadly incidents occurred on very short slopes (<70 metres of relief) outside mountainous areas. Only five fatalities were related to backcountry recreational activities in highlands. The inventory of avalanche-threatened areas has never been completed in the Province of Québec and it is likely that avalanche-prone areas are more widespread than previously thought. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Logistics operations are interwoven among the very fabric of emergency management and no aspect of a health care organization’s business processes goes untouched by tenable supply chain management. The purpose of this work is to provide lessons observed during a response and recovery scenario resultant of a snow avalanche that occurred in Afghanistan north of Kabul. The lessons documented throughout this work are specific to how Soldiers, while deployed in support of Operation Enduring Freedom, were faced with one of the most unlikely of scenarios conceivable – responding to a natural disaster. In this work are observations, relayed by organization-level leadership during a deliberate After Action Review (AAR) related to communications, preparedness, warehouse security, the development of cross-functional teams, the adherence by clinical teams to a single source of supply, equipment and supply accountability, and the development of appropriate pre-configured push packs to support future scenarios such as the one experienced on February 9, 2010. [ABSTRACT FROM AUTHOR]

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 bad 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 bad 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Rockfall and snow avalanche events often cause injury to European larch (Larix decidua Mill.) trees, giving rise to the formation of callus tissue and tangential rows of traumatic resin ducts (TRDs).We analyzed and quantified anatomical reactions of juvenile trees injured before the start of the growing season by snow avalanches (15 trees, 324 cross sections) or rockfalls (18 trees, 270 cross sections). Traumatic resin ducts were observed in the growth ring formed following injury in 94.3% of the rockfall samples and 87.3% of the snow avalanche samples. Traumatic resin ducts were formed at the beginning of the new annual ring around wounds caused by rockfalls. In contrast, in trees injured by snow avalanches, TRDs were not formed until after the formation of several rows of early earlywood (EE) tracheids (mean ± SD = 4.19 ± 2.56 rows). The dimensions of the EE tracheids observed in the snow avalanche samples were greatly reduced in the tissues bordering the wound, with radial width reaching an average of only 50% and lumen cross-sectional area an average of only 46% of pre-event values. It is therefore possible to differentiate injuries due to past snow avalanches from injuries due to rockfall based on anatomical growth reactions in the tissues bordering scars. [ABSTRACT FROM AUTHOR]

The porosity of the snow surrounding the air pocket favors oxygen diffusion from snow into the air pocket, whereas exhaled carbon dioxide diffuses in the opposite direction and is buffered in the snow. The ERC recommends assessing airway patency in subjects buried by an avalanche.[2] The present study[1] suggests also to consider the presence of an air pocket as a positive survival marker in avalanche burial, in agreement with previous experimental[[3], [5]] and epidemiological[4] data. [Extracted from the article]

Rule-based decision frameworks are widely recommended to estimate the avalanche risk while planning a ski tour. However, these frameworks were developed relying primarily on accident data and usually did not consider backcountry travel data. Hence, they are not risk-based. Here, we address this gap and calculate the risk taken during backcountry touring in avalanche terrain and correlate it to the expected avalanche conditions as described in a public avalanche forecast. For this, we rely on 784 reported avalanche accidents and more than 2.1 million movement points in potential avalanche terrain, based on GPS tracks recorded in Switzerland for 14 winter seasons. Combining this data with the respective avalanche forecast, we show that risk increases fourfold from danger level 1-Low to 2-Moderate, and from 2-Moderate to 3-Considerable. Furthermore, at 2-Moderate and 3-Considerable, in the critical elevations and aspects specified in the avalanche forecast, the risk is nearly six times higher compared to locations outside this, so-called, core zone. For danger level 1-Low, where the Swiss avalanche forecast does not provide any information about the critical elevations and aspects, we derived a risk-based core zone. Within this core zone too, the risk is about six times higher than outside. These findings suggest an adaption of the rule-based decision frameworks to reflect the observed risk better. The proposed framework considers the strong influence of the elevation and reduces the effect of the aspect, compared to former decision frameworks. We emphasize that this new decision framework cannot replace on-site risk assessment. However, it allows backcountry users to come closer to the goal of achieving a minimum of avalanche risk while allowing a maximum of freedom of movement. • Avalanche risk on backcountry ski tours calculated from accident and movement data. • Large data sets: 784 avalanche accidents, 2 million GPS points from ski touring. • The risk correlates strongly with the information of the avalanche forecast. • The avalanche risk quadruples from one danger level to the next. • First completely data-based decision framework for travel in avalanche terrain. [ABSTRACT FROM AUTHOR]