Developing nationwide avalanche terrain maps for Norway

Abstract

Snow avalanches are a significant natural hazard in Norway. One method to manage the backcountry avalanche hazard is through detailed mapping of avalanche terrain. Avalanche terrain can be mapped using a variety of methods, including using the Avalanche Terrain Exposure Scale (ATES); however, manual classification of terrain using ATES is time consuming. This study has developed and compared a fully automated algorithm to provide ATES mapping for all of Norway. Our new algorithm is based on the technical model for ATES mapping. This model has specific terrain-based thresholds that can be applied for automated terrain-based modeling. Our algorithm expands on prior work by including the potential release area (PRA) model to identify and calculate the likelihood of an avalanche releasing from a start zone. We also use the raster-based TauDEM-model to determine the avalanche runout length. The final product is a 10-m resolution ATES map. We compared this nationwide ATES map with areas that have been manually mapped by avalanche experts, and find that the automated approach yields similar and reliable results. In addition to comparing mapped areas, we also examine manually mapped linear routes and compare these with the automated mapped ATES areas. Our results suggest that for open terrain, the vast majority of the manually classified tracks are predominantly in the same ATES class as our algorithm. For forested areas, we get mixed results, which can be attributed to a lack of suitable vegetation data at an appropriate scale. Despite this limitation, the current ATES algorithm and resulting spatial data are already valuable as a large portion (~ 70%) of the Norwegian backcountry terrain is above tree line. The automated algorithm is also useful to ensure consistent manual classification across different regions in Norway, or globally, and will permit greater reproducibility and easier updating of mapping for the future.

Insight into real-world complexities is required to enable effective response from the aquaculture sector to climate change

“…disruption of power supplies and damaged buildings and infrastructure [66]. Heatwaves, or sudden temperature changes, and/or precipitation can lead to avalanches, rockfalls, and landslides which can result in infrastructure damage [67,68].…”

“…Hazards of road transportation include accidents, especially in winter months [226], and the road network is often affected or damaged by winter floods, avalanches and landslides [227]. Heavy rainfall is one of the main triggers for landslides, although erosion, snowmelt and weathering of bedrock are also factors [67], and precipitation and rapid temperature changes are triggers for snow avalanches [68]. Increased temperatures may affect storage and transportation times.…”

Automated avalanche hazard indication mapping on a statewide scale

“…Even though an avalanche runout model is applied, only one scenario is calculated. Larsen et al (2020) developed an avalanche terrain exposure scale (ATES) for Norway, applying the raster-based TauDEM model. Issler (2020) developed NAKSIN, a new methodology for avalanche hazard indication maps in Norway.…”

Travel and terrain advice statements in public avalanche bulletins: A quantitative analysis of who uses this information, what makes it useful, and how it can be improved for users

“…To further assist recreationists in selecting appropriate terrain, various products have been developed including specialized maps, decision aids, and web applications. For example, Statham et al (2006) the avalanche terrain exposure scale (ATES) to describe the severity of backcountry trips with respect their general exposure to avalanche hazard using the qualitative terms 'simple', 'challenging ', and 'complex'. This expert terrain rating system has been used extensively to rate backcountry recreation areas in Canada (see https://www.avalanche.ca/planning/trip-planner), but ATES has also been applied in Norway (Larsen et al, 2020), Spain (Gavalda et al, 2013) and Switzerland (Pielmeier et al, 2013). While the ATES system provides an expert assessment of the terrain, Harvey et al, (2018) took a more physical process-oriented approach to classifying terrain when developing avalanche terrain maps based on GIS algorithms that explicitly identify potential avalanche release areas, possible runout zones, areas with the potential for remote triggering, and areas where small or medium-sized avalanches might lead to serious injures or deep burials due to terrain traps.…”