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This paper presents the reconstruction results of catastrophic avalanche characteristics. The avalanche occurred on the slope of the Gora Otdelnaya ski resort on January 9, 2021 (Norilsk). It had a peak pressure of 0.266 MPa and led to the destruction of a suburban settlement, covering an area of about 0.9 ha. Six people got caught in the avalanch, of whom three were killed. The virtual and calculated boundaries of the maximum avalanche run-out distance are given. The causes of the catastrophe are also under investigation. An avalanche hazard assessment methodology for the Russian Arctic region and other poorly studied areas with no long-term avalanche observations is suggested.

Snow avalanches are a common natural hazard in many countries with seasonally snow-covered mountains. The avalanche hazard varies with snow avalanche type in different snow climate regions and at different times. The ability to understand the characteristics of avalanche activity and hazards of different snow avalanche types is a prerequisite for improving avalanche disaster management in the mid-altitude region of the Central Tianshan Mountains. In this study, we collected data related to avalanche, snowpack, and meteorology during four snow seasons (from 2015 to 2019), and analysed the characteristics and hazards of different types of avalanches. The snow climate of the mid-altitude region of the Central Tianshan Mountains was examined using a snow climate classification scheme, and the results showed that the mountain range has a continental snow climate. To quantify the hazards of different types of avalanches and describe their situation over time in the continental snow climate region, this study used the avalanche hazard degree to assess the hazards of four types of avalanches, i.e., full-depth dry snow avalanches, full-depth wet snow avalanches, surface-layer dry snow avalanches, and surface-layer wet snow avalanches. The results indicated that surface-layer dry snow avalanches were characterized by large sizes and high release frequencies, which made them having the highest avalanche hazard degree in the Central Tianshan Mountains with a continental snow climate. The overall avalanche hazard showed a single peak pattern over time during the snow season, and the greatest hazard occurred in the second half of February when the snowpack was deep and the temperature increased. This study can help the disaster and emergency management departments rationally arrange avalanche relief resources and develop avalanche prevention strategies.

Glacial avalanche hazard poses threat to human lives and damage settlements / infrastructures in alpine glaciers mountainous regions. A gigantic ice plus rock avalanche destroyed Gyari military camp in Siachen sector on April 2012 and buried 139 personals. The study focuses on geospatial analysis and simulation of Shishper glacial avalanche of Hunza basin. To simulate the potential glacial avalanche hazard to Hassan Abad settlements, an empirical process based Glacier Avalanche Model; Rapid Access Mass Movement Simulation (RAMMS) is utilized. The model encompasses avalanche release area and height for the execution of simulation. The model output of Shishper glacial avalanche resulted; a max pressure of 450 Kpa, max velocity of 40 m/s, and the max flow height of 80m, while the resulted surge extent output was 2500m. The potential hazardous Shishper glacial avalanche remains a continuous hazard to Hassan Abad of Hunza valley including Karakoram Highway and Frontier Works Organization (FWO) camp. The study has resulted in identifying the Upper Indus Bain (UIB) being more prone to glacial avalanche hazards because of host factors in general and the anthropogenic factor in particular.

The legislation of the Russian Federation establishes the need to take into account hazardous natural processes and their parameters in territorial planning, as well as presentation of them in the relevant documentation in the form of maps. In a number of countries, there is a long-standing practice of mapping the avalanche zones basing on the definition of different levels of danger, which are used to limit or ban the construction in avalanche zones, as well as to project the anti-avalanche activities. Russia has experience in assessing risk and mapping the avalanche danger, but the practice of making such plans in our country is still not developed. The purpose of this work is to determine and plot on map avalanche zones on the example of one of the actively developed mountain regions of Russia. The all-season mountain resort «Gorky Gorod», located on Krasnaya Polyana in the Krasnodar region, was chosen as the object of study. Two approaches to the accounting and mapping of avalanche hazard in territorial planning were tested. In the first case, occurrence and pressure of avalanches were the determining factors. In the second case, critical avalanche pressure values were used to determine their destructive impact effect. To determine indexes (indicators) of the avalanche hazard, the simulation of snow avalanches in the RAMMS program was performed. According to the results of modeling for area of the «Gorky Gorod» resort schemes of the avalanche zones were constructed on the basis of two different approaches, having no account for the anti-avalanche measures used there. A more detailed plan based on a combination of these two approaches had also been drawn up and analyzed. The required criteria for determining the boundaries of zones with different levels of the danger are the subject for discussion. However, the proposed division of avalanchedangerous territory into zones with different levels of the hazard at the stage of territorial planning meets the requirements of the legislation and contributes to improving human security, reducing the avalanche risk, and mitigating the consequences of emergencies caused by avalanches.

Avalanche climatology is defined as the study of the relationships between climate and snow avalanches, and it contributes in aiding avalanche hazard mitigation efforts. The field has evolved over ...

Little Cottonwood Canyon Highway is a dead-end, two lane road leading to Utah's Alta and Snowbird ski resorts. It is the only road access to these resorts and is heavily traveled during the ski season. Fifty-seven percent of this road has been calculated to fall within known avalanche paths and the road is ranked among the most dangerous highways in the world relative to avalanche hazard. Professional avalanche forecasters monitor this road throughout the ski season in order to make road closure decisions in the face of avalanche danger. Forecasters at the Utah Department of Transportation avalanche guard station at Alta have maintained an extensive daily winter database on explanatory variables relating to avalanche prediction. Whether or not an avalanche crosses the road is modeled in this paper via Bayesian additive tree methods. Utilizing daily winter data from 1995 to 2010, results show that using Bayesian tree analysis outperforms traditional statistical methods in terms of realized misclassification costs that take into consideration asymmetric losses arising from two types of errors. Closing the road when an avalanche does not occur is an error harmful to resort owners and not closing the road when one does may result in injury or death.

Avalanches constitute risky situations especially for mountainous areas in the eastern part of Turkey. According to records of the Disaster and Emergency Management Presidency, avalanches have killed 30 people per year in Turkey over the last 30 years. Developing winter tourism also affects losses. For example, an avalanche occurred in Torul, Köstere, in the province of Giresun, on January 25, 2009, which killed 10 mountaineers and injured 7 people. This research is focused on, known fatal avalanches and avalanche mitigation works. The obtanied map provides are reliable and easy to understand information where avalanches contstitue risksy sitation in regional scale as well as where new avalanche paths may develop under favourable conditions. Moreover the figure of avalanche hazard situation is presented to construct a picture of the potential threats. This paper provides information about avalanche fatalities and avalanche mitigation works in Turkey.

Avalanches pose a significant problem in most mountain regions of Russia. The constant growth of economic activity, and therefore the increased avalanche hazard, in the North Caucasus region lead to demand for the development of large-scale avalanche risk assessment methods. Such methods are needed for the determination of appropriate avalanche protection measures as well as for economic assessments.The requirement of natural hazard risk assessments is determined by the Federal Law of the Russian Federation (Federal Law 21.12.1994 N 68-FZ, 2016). However, Russian guidelines (SNIP 11-02-96, 2013; SNIP 22-02-2003, 2012) are not clearly presented concerning avalanche risk assessment calculations. Thus, we discuss these problems by presenting a new avalanche risk assessment approach, with the example of developing but poorly researched ski resort areas. The suggested method includes the formulas to calculate collective and individual avalanche risk. The results of risk analysis are shown in quantitative data that can be used to determine levels of avalanche risk (appropriate, acceptable and inappropriate) and to suggest methods to decrease the individual risk to an acceptable level or better. The analysis makes it possible to compare risk quantitative data obtained from different regions, analyze them and evaluate the economic feasibility of protection measures.

The snow and avalanche climate types maritime, continental and transitional are well established and have been used extensively to characterize the general nature of avalanche hazard at a location, study interseasonal and large-scale spatial variabilities and provide context for the design of avalanche safety operations. While researchers and practitioners have an experience-based understanding of the avalanche hazard associated with the three climate types, no studies have described the hazard character of an avalanche climate in detail. Since the 2009/10 winter, the consistent use of Statham et al.'s (2017) conceptual model of avalanche hazard in public avalanche bulletins in Canada created a new quantitative record of avalanche hazard that offers novel opportunities for addressing this knowledge gap. We identified typical daily avalanche hazard situations using Self Organizing Maps (SOM) and then calculated seasonal prevalence values of these situations. This approach produces a concise characterization measure that is conducive to statistical analyses, but still provides a comprehensive picture that is informative for avalanche risk management due to its link to avalanche problem types. Hazard situation prevalence values for individual seasons, elevations bands and forecast regions provide unprecedented insight into the interseasonal and spatial variability of avalanche hazard in western Canada.

We explore the problems concerning the territorial distribution of the population in avalanche-hazardous zones of Sakhalin oblast. Avalanches present hazard to almost half the settlements of oblast, and to about 400 km of trunk routes. Data are provided for avalanche disasters that occurred in the territory of Sakhalin oblast during 1928 to 2012 as well as on the present state of avalanche prevention and mitigation.

This study demonstrates the effectiveness of remote sensing and analytical hierarchy process for avalanche hazard mapping. The layers incorporated in this study were of slope, aspect, profile curvature, ground cover and elevation. The accuracy of output was determined using the registered avalanche sites based on ground observations and field-based modelling techniques. 93.35% of avalanche-affected areas came under maximum and moderate hazard zones, thus proving the effectiveness of this technique for Gangotri glacier basin. A parallel study was done to observe the change in the results, if any, by using high-resolution DEM and Cartosat-1 imagery. Similar methodology was adopted and the outcome was having significant improvement over the previous result as 98.8% of the preregistered avalanche area falling within maximum and moderate hazard zones.

This paper presents an assessment of the avalanche hazard potential and the resulting risks on mountain roads for a 38.7-km-long section of road no 76 (Siglufjarðarvegur) in northern Iceland following a regional scale approach developed in the Alps. The assessment of the individual avalanche death risk proved applicable to distinguish areas of avalanche hazard with a risk above the accepted level, which should be given priority in following detailed investigations and the planning of possible protective measures, from road sections where the avalanche death risk is low and accepted according to international practice. The cumulative individual and collective avalanche death risks in the investigated road section provide a comparable measure for assessing the avalanche hazard both within the Icelandic public road network and on an international scale. The case study on road no 76 in northern Iceland shows that a standardised regional scale risk-based approach is practical to determine, analyse and assess the avalanche hazard situation on mountain roads in Iceland and guarantees comprehensible, reproducible and comparable results as a basis for a sustainable planning of measures.

Reported avalanche fatalities in the United States increased markedly through the latter half of the twentieth century, a result of the increasing popularity of winter sports. Despite this increase, the literature concerning US avalanche fatalities is sparse. This paper presents a comparison of three US databases containing avalanche fatality information: Storm Data, the West Wide Avalanche Network (WWAN) dataset, and the National Avalanche Database (NAD). The frequency of avalanche fatalities, their temporal trends, spatial distributions, and the demographic characteristics of the victims were analyzed in each database for the years 1998–2009 for the US mountainous west. The data were then pooled to arrive at an estimate of avalanche fatality frequency in the United States for the study period. While the results indicate a considerable amount of overlap between the datasets, Storm Data reports fewer avalanche fatalities than both the WWAN and NAD datasets. All three datasets report a maximum of fatalities in January and display three spatial maxima: the Rocky Mountains of west-central Colorado, the intermountain region from central Utah through Idaho to west-central Montana, and the northern Cascade Ranges of Washington; however, a large void appears in the Storm Data records in the vicinity of the Montana maximum. These maxima result from a juxtaposition of avalanche hazard in these mountainous environments with a high concentration of winter sports activities.

This paper presents a snow avalanche hazard map of the most avalanche-prone mountain range in the Czech Republic, the Krkonose Mountains. The map was prepared using historical records of 1132 avalanches which occurred over the last 54 years and state-of-the-art modelling of avalanche propagation and the spatial distribution of potential avalanche source areas. The map provides not only reliable and easy to understand information for the Mountain Rescue Service of the Czech Republic and mountain tourists, but also for land use managers to identify areas where new avalanche paths may develop under favourable conditions, including the total removal of forest cover.

Snow avalanches pose a serious threat in alpine regions. They may cause significant damage and fatal accidents. Assessing the local avalanche hazard is therefore of vital importance. This assessment is based, amongst others, on daily collected meteorological data as well as expert knowledge concerning avalanche activity. To a data set comprising meteorological and avalanche data collected for the Canton of Glarus in Eastern Switzerland over a period of 40 years, we applied different machine learning strategies aiming at modeling a decision support system in avalanche forecasting.

System identification methods are applied to predict avalanche hazard. A tenyear record of avalanche hazard and snow cover from Davos and Weissfluhjoch in the Swiss Alps is analyzed. Several models are estimated and validated. Dynamic models present a substantial improvement in the quality of hazard predictions compared to predictions derived from a commonly used static nearest neighbor model structure. Further possible modeling improvements are briefly discussed.

Snow avalanches can pose a risk to persons, buildings, and infrastructure in mountainous regions. As long as people have settled in the Alps, they had to deal with avalanche hazard. Structural mitigation measures, protection forests, and land-use planning reduced the hazard and the risk in the past decades and contributed thereby to the development of mountain regions. In many countries, decisions on dealing with the consequences of avalanches are increasingly based on the assessment of risks and not only on the reduction of hazard. In the first part of this chapter, we present different elements of an integrative risk management of avalanches with a focus on Switzerland. In the second part, we present an example of how this concept can be applied to handle the avalanche risk in the City of Juneau, Alaska.

Snow avalanches are a major natural hazard in most snow-covered mountain areas of the world. They are rapid, gravity-driven mass movements and are considered a meteorologically induced hazard. Snow avalanches are one of the few hazards that can be forecast, and in situ measurements of instability are feasible. Advanced hazard-mitigation measures exist, such as land-use planning based on modeling avalanche dynamics. The most dangerous snow avalanches start as a dry-snow, slab avalanche that is best described with a fracture mechanical approach. How fast and how far an avalanche flows is the fundamental question in avalanche engineering. Models of different levels of physical complexity enable the prediction of avalanche motion. Although the avalanche danger (probability of occurrence) for a given region can be forecast—in most countries with significant avalanche hazard, avalanche warnings are issued on a regular basis—the prediction of a single event in time and space is not (yet) possible.

Avalanche impacts in Canada, including fatalities, are summarized for residential and public areas, as well as roads, ski areas, backcountry recreation, and resource industries. Methods for managing avalanche hazard, which include defence structures, zoning, forecasting and explosive control, are outlined. Problems with current avalanche hazard management are identified and progress at solving these problems is identified with an emphasis on residential areas, backcountry recreation and resource industries.

Avalanches represent a very short, local, dynamic event in snow-covered mountainous regions. They are not easy to predict and often can produce devastating results. Avalanche cartography deals with the causes and consequences of such incidents and attempts to depict them in a variety of ways. The most common cartographic representation within this field is the avalanche hazard map. It incorporates mainly large-scale topographic elements with thematic features. However, besides just visualizing what has happened and depicting locations of potential risk, it is now possible within modern cartography to experiment with different approaches and to visualize complex variables in a cartographically demanding way. This paper deals with the phenomena of avalanches from a cartographic perspective and shows the variety of possibilities cartography can offer today to understand and predict these complex natural hazards. Situees dans les regions montagneuses couvertes de neige, les avalanches representent un evenemen...

Snow avalanches are a cold-season natural hazard in the Glacier National Park (GNP), Montana, region. They are responsible for the closure of critical transportation routes, property damage, and, on occasion, fatalities. This study examined local newspaper reports of avalanches during the period from 1949 to 1997 and found a tendency for El Nino years to be associated with a decrease in snow avalanches in the region. This decrease in frequency may be caused by the below-normal precipitation that occurs in the region during El Nino years. Additional factors, such as primary storm-track direction, and temperature cycling also should be examined. [Key words: snow avalanches, El Nino, Glacier National Park (GNP).]

During the ski season, professional avalanche forecasters working for the Utah Department of Transportation (UDOT) monitor one of the most dangerous highways in the world. These forecasters continually evaluate the risk of avalanche activity and make road closure decisions.

Each year in the Carpathian Mountains and the Sudety Mountains snow avalanches cause a great number of accidents. Avalanches also threaten buildings and affect the environment. The latest studies in Poland aim to implement advanced snow avalanche hazard mapping procedures, which would allow the creation of complex cartographic products for the location of avalanche hazard areas. These preliminary studies showed that results of these procedures strongly depend on the quality of the input digital surface data. The main goal of this study is to investigate this problem in detail through comparison of different types of Digital Elevation Models (DEMs), putting stress on high resolution DEMs generated from airborne and terrestrial laser scanning, in the context of estimating potential avalanche release areas and making run-out calculations. Test sites in the Tatra Mountains in the Carpathians and in the Karkonosze Mountains in the Sudety Mountains were selected for this study. The analysis was performed using Swiss Rapid Mass Movements (RAMMS) model and modified script on delineation automated release area. The study recognized that not only quality but also resolution of a digital surface models influence the accuracy of release area and volume estimation, calculated topography parameters, location of avalanche track and other parameters calculated by dynamic models.

The avalanche hazard in the United States is most severe in the continental zone of Colorado, where property damage and deaths exceed those in any other state. The continental zone is normally characterized by a shallow snowpack, faceted crystal growth, and relatively fewer avalanches as compared to the coastal and intermountain zones farther west. This study illustrates that variations in the avalanche character in the continental zone may, at times, resemble some less continental characteristics that are found farther west as a result of anomalous atmospheric circulation patterns. Results from cluster analyses show that some sites in the southern portion of the continental zone generally represent a less continental character. Anomalies of 500-mb heights explain the variability of avalanche climates for selected sites, particularly for Berthoud Pass, within the continental zone. Negative heights over the southwestern United States during early winter correspond with less continental conditions, but the ...

Since avalanche hazard mapping is a very time-consuming affair, it is our objective to develop an appropriate method to map large remote areas. This is based on satellite imagery and on a digital elevation model (DEM) tested at two sites in the Swiss Alps. To simulate the avalanche hazard, the existing Salm-Voellmy model was modified for the computer environment and extended to include the characteristics of avalanches within forested terrain. The forests were classified with Landsat Thematic Mapper (TM) data. So far, only a single forest class has been established. While the separation of forest, shrub and non-forested areas near the timberline poses problems, the classification of small openings and avalanche tracks inside the forest was successful. Comparison with the existing avalanche cadastral map revealed that 85 per cent of the risk areas were correctly classified. Separation into the defined ‘red’ and ‘blue’ danger zones, on the other hand, was not satisfactory. For an operational application, further improvements are necessary. However, the general approach is very promising and should lead to more reliable hazard maps for planning purposes, as well as to new and better insights into the mutual interactions between snow and forest.

OBJECTIVE: We investigated whether frequency of avalanche accidents corresponds with the danger assessment given in avalanche hazard tables and with topographic factors of the avalanche origin. METHODS: A retrospective review of official avalanche surveillance data and of medical reports from helicopter-based emergency medical systems was conducted. RESULTS: Most victims involved in avalanche accidents are ski tourers and off-piste skiers, about 90% are male, and age ranges from 10 to more than 70 years. Sixty-seven percent of accidents occurred when moderate and considerable danger was forecast. In 94.0% of accidents avalanches were triggered by victims themselves or by nearby recreationists; 32.6% of avalanche slides occurred on extremely steep slopes at gradients exceeding 40 degrees . Overall incidence of accidents before noon was 25.0%. Professional stand-by avalanche parties significantly contributed to rescuing avalanche victims, but the chance of survival is diminished when arrival was delayed. All patients who were able to free themselves from avalanche burial survived. Of those rescued by companions, 78.0% survived compared with only 10.0% of those rescued by organized rescue teams (P

In Kazakhstan, area of 124 thousand km 2 is prone to the avalanche hazard. Avalanches are released down in mountain regions situated along the eastern boundary of Kazakhstan. Systematic studies of avalanches here were started in 1958 by explorer I.S. Sosedov; later on, I.V. Seversky continued these investigations in Institute of Geography of the Kazakh Soviet Republic. Actually, he founded the Kazakh school of the avalanche studies. In 1970–1980s, five snow-avalanche stations operated in Kazakhstan: two in Il’ Alatau, two in Zhetysu Alatau, and one in the Altai. At the present time, only two stations and two snow-avalanche posts operate, and all of them are located in Il’ Alatau. Since 1951 to 2013, 75 avalanches took place in Kazakhstan, releases of them caused significant damages. For this period 172 people happened to be under avalanches, among them 86 perished. Large avalanche catastrophes causing human victims and destructions took place in Altai in 1977 and in Karatau in 1990. In spring of 1966, only in Il’ Alatau avalanches destroyed more 600 ha of mature fir (coniferous) forest, and the total area of forest destroyed here by avalanches amounts to 2677 ha or 7% of the total forest area. For 48 years of the avalanche observations, there were 15 winters with increased avalanche activity in the river Almatinka basin when total volume of released snow exceeded annual mean value of 147 thousand m 3 . During this period, number of days with winter avalanches changed from three (in season of 1973/1974) to 28 (1986/1987), the average for a year is 16 days for a season. Winter with the total volume of snow 1300 thousand m 3 occur once in 150 years. Individual avalanches with maximal volume of 350 thousand m 3 happen once in 80 years. Preventive avalanche releases aimed at protection of roads and settlements are used in Kazakhstan since 1974. These precautions are taken in Il’ Alatau, Altai, and on Kalbinsky Range. Avalanches are released with the use of explosives. Protective constructions are built very rarely. The most large-scale project is the protection of the Medeo skating-rink in Il’ Alatau where in 1974 special snow-retentive boards of wooden beams on metal supports were constructed on the above located slope. The provision of safety against avalanches becomes especially actual problem in view of development of the mountain-skiing resorts in Il’ Alatau, Zhetysu Alatau, and Altai.

Canadians claim that the recently constructed Coquihalla Highway over the Rocky Mountains is one of the most spectacular and scenic superhighways in the world (Fig. 1). Unfortunately in winter snow avalanche activity is widespread and about 150 avalanche sites affect almost 17 km of the route. In one critical area a roof structure called the Great Bear Snow Shed has been constructed over the highway to protect traffic throughout the winter. This particular area of extreme avalanche hazard has a history of high avalanche frequency. Here heavy snowfall, steep terrain and adverse geological factors combine to create potentially unsafe ground above the road (Fig. 2). The Coquihalla Highway is a four-lane dual carriage-way and the only tollway in British Columbia. It starts approximately 200 km east of Vancouver near the township of Hope on the Trans-Canada Highway and runs northeastwards for 195 km through Merritt to rejoin the Trans-Canada Highway at Kamloops. The new highway follows a series of mountain corridors through the rugged Cascade Ranges and thereby reduces the Hope-Kamloops travel distance by 80 km. The main corridors are primarily glacial in origin and contain extensive deposits of moraine and fluvioglacial drift in the valley bottoms. Along the route elevations greater than 1900 m are commonplace and relief may be as much as 1300 m. The annual snowfall in this part of the Cascade Range is usually less than 8 m, but in particularly cold years the snowpack may reach depths of more than 16 m. Extensive drifting during

Predicting heavy mountain snowfall, which is critical for avalanche hazard forecasting, is difficult due to complex interactions between rugged topography and atmospheric circulation. In this study the relationship between atmospheric circulation patterns and extreme snowfall events is examined at Bridger Bowl, Montana, U.S.A. which has a 26-year winter record of daily snowfall. Five hundred millibar composite and anomaly maps were constructed for days of heavy snowfall (greater than 32.8 cm). These maps show that during and prior to heavy snowfall, Bridger Bowl is located beneath the back side of a upper-level trough, with predominant winds and storms coming from the northwest. This atmospheric circulation pattern differs from those for other high-elevation sites in the North American interior due to the surrounding regional topography. High mountain ranges to the southwest and west often block incoming moisture, while relatively lower topography to the northwest allows Pacific moisture to reach Bridger Bowl. The results of this study can be used to complement operational forecasting models for predicting heavy snowfall at Bridger Bowl, thereby facilitating snow avalanche forecasting in the region.

This is a report on the avalanche hazard area of Rebun-island, northern Hokkaido, researched on March and August in 1966.1. There are slopes of marine terraces along the coast, on which snow-cornice and -drift are usually formed by heavy wind in winter. They often developed to snow avalanches and caused large damages.2. From late February to early March in 1966, air temperature became very high and many ground avalanches broke out. The layer of depth hoar or of wet granular appeared to play an important part in these avalanches formation and release. Potential Magnitude (P.M.) of these avalanches were generally 3.0-4.0 and maximum 5.1.3. The earth wind-baffle on the terrace is successful. On the longer slope, however, it is necessary to make both, the wind-baffle on the terrace and the defence structure in the sliding zone.

PLANNING AND OPERATIONAL PROCEDURES ARE PRESENTED, AND CRITERIA FOR AVALANCHE CONTROL AND THE EVALUATION OF AVALANCHE HAZARD ARE DISCUSSED BASED ON FIELD DATA. A METHOD FOR DETERMINING WHEN GUNFIRE SHOULD COMMENCE IS OUTLINED. BASIC INFORMATION NECESSARY FOR FORMULATING OPERATIONAL FORECASTS FOR HIGHWAY MAINTENANCE AND AVALANCHE CONTROL PERSONNEL IS GIVEN BASED ON: MOUNTAIN WEATHER FORECASTS, TRAFFIC DENSITY, AND CURRENT SNOW CONDITIONS. INSTRUMENT NEEDS ARE EXPLAINED IN DETAIL. /AUTHOR/

The road along the Óshlíð hillside in the West Fjords region of Iceland is one of the most hazardous roads in Iceland due to avalanches, rockfalls and debris flows. The road has little traffic, but nevertheless traffic accidents caused by the severe conditions at the site are common. A number of avalanche tracks are found on the hillside. In some of these tracks, avalanches occur more frequently than in others. When there is an avalanche threat, avalanches generally flow over many tracks in a short time. Monitoring vibrations in the tracks with the highest avalanche frequency can indicate when avalanches start flowing down the hillside in a snowstorm, and avalanche hazard can then be declared with the specific site indicated. The same methodology can be used for rockfalls and debris flows, which are strongly affected by weather conditions and typically occur in clusters. Based on this knowledge, a research project was initiated in February 1996 with the objective of developing an automatic system based on seismic measurements to detect and analyze avalanches on the Óshlíð hillside and to instantly send a warning to a control station.

To the Editor:— The article on snowmobile injuries ( 209 :1672, 1969) by Chism and Soule evokes another facet of the problem which needs emphasis. This is the need for training in winter survival, winter first aid techniques, and hazard recognition. In Montana during the past winter, a man and his son died after their snowmobile fell through the ice on Yellowtail Reservoir. Another serious problem is avalanche hazard. The National Ski Patrol System has developed a slide lecture on avalanche hazard which members are happy to present at meetings of snowmobile organizations. Those of us who are experienced in ski touring are aghast at the potential problems posed by large numbers of untrained individuals in poor physical condition, many miles from assistance.