Validation points, validation area, ground truth coverage, SPOT 6 avalanche outlines, Sentinel-1 avalanche outlines, Sentinel-2 avalanche outlines, Davos avalanche mapping (DAvalMap) avalanche outlines as shapefiles and a detailed attribute description (DataDescription_EvalSatMappingMethods.pdf). Coordinate system: CH1903+_LV95 The generation of this dataset is described in detail in: Hafner, E. D., Techel, F., Leinss, S., and Bühler, Y.: Mapping avalanches with satellites – evaluation of performance and completeness, The Cryosphere, https://doi.org/10.5194/tc-2020-272, 2021.

Drone-Based Avalanche Radar Mapping Market Outlook

According to our latest research, the global drone-based avalanche radar mapping market size reached USD 222.5 million in 2024. The sector is experiencing robust growth, with a CAGR of 16.7% projected from 2025 to 2033. By the end of 2033, the market is forecasted to attain a value of USD 728.4 million. This impressive expansion is primarily driven by technological advancements in drone platforms, rising demand for real-time avalanche risk assessment, and increased governmental focus on public safety in mountainous and snow-prone regions.

One of the key growth factors propelling the drone-based avalanche radar mapping market is the increasing frequency and severity of avalanches worldwide due to climate change. As global temperatures rise, snowpack stability becomes more unpredictable, leading to heightened avalanche risks in alpine regions. This has compelled government agencies and emergency response teams to invest heavily in advanced technologies that can provide timely and accurate avalanche detection and mapping. Drone-based radar solutions offer significant advantages over traditional ground-based methods, including rapid deployment, access to hard-to-reach areas, and the ability to gather real-time data even in adverse weather conditions. These benefits are crucial for both preventive risk assessment and swift rescue operations, making drone-based systems an indispensable tool in modern avalanche management strategies.

Another significant driver is the continuous innovation in radar and sensor technologies integrated within drone platforms. The adoption of sophisticated tools such as synthetic aperture radar (SAR), ground penetrating radar (GPR), and LiDAR has enhanced the capability of drones to penetrate snow layers and generate high-resolution, three-dimensional maps of avalanche-prone zones. These technological advancements have not only improved the accuracy of avalanche forecasting but have also expanded the application scope to include detailed research, long-term monitoring, and environmental impact assessments. Furthermore, the integration of artificial intelligence and machine learning algorithms with radar data analytics is enabling predictive modeling, which supports proactive decision-making for avalanche mitigation and rescue operations.

The growing collaboration between governmental bodies, research institutes, and commercial operators is further fueling market expansion. Public-private partnerships are facilitating the development and deployment of tailored drone-based avalanche mapping solutions that cater to specific regional needs. In addition, increased funding for research and innovation in disaster management technologies is accelerating the commercialization of advanced drone systems. The market is also witnessing a surge in service-based business models, wherein specialized companies offer end-to-end avalanche mapping and risk assessment services to governmental and private entities. This trend is expected to continue, given the rising awareness about the economic and human costs associated with avalanche disasters.

From a regional perspective, Europe currently dominates the drone-based avalanche radar mapping market, owing to its extensive alpine regions, well-established ski tourism industry, and proactive regulatory frameworks supporting drone operations. North America follows closely, driven by significant investments in public safety infrastructure and a strong presence of technology providers. The Asia Pacific region is emerging as a high-growth market, attributed to increasing adoption of advanced monitoring technologies in countries with expansive mountainous terrains such as China, Japan, and India. Meanwhile, Latin America and the Middle East & Africa are gradually recognizing the importance of drone-based solutions for disaster management, with several pilot projects and government initiatives underway.

Component Analysis

The component segment of the drone-based avalanche radar mapping market is broadly categorized into hardware, software, and services. Hardware forms the backbone of this market, encompassing the drones themselves, radar sensors, LiDAR units, and associated payloads necessary for avalanche detection and mapping. Advances in miniaturization and ruggedization of radar sensors have enabled drones to carry sophisticated payloads without compromising flight endurance, thus enhancing operational efficiency. Furthermore, the int

Drone-Based Avalanche Radar Mapping Market Outlook

According to our latest research, the global drone-based avalanche radar mapping market size reached USD 412.5 million in 2024. The market is expected to grow at a robust CAGR of 13.8% from 2025 to 2033, reaching a projected value of USD 1,198.2 million by 2033. This impressive growth trajectory is primarily fueled by the increasing adoption of advanced drone technologies for avalanche risk mitigation, enhanced accuracy in snowpack analysis, and the growing focus on public safety in mountainous and snow-prone regions worldwide. As per our latest research, the integration of radar mapping with unmanned aerial vehicles (UAVs) is revolutionizing avalanche prediction and rescue operations, making it a pivotal technology in the fight against natural disasters.

One of the most significant growth factors driving the drone-based avalanche radar mapping market is the rising incidence of avalanches due to climate change and increased human activity in mountainous regions. With global warming leading to unpredictable snow patterns and more frequent extreme weather events, the need for accurate, real-time avalanche monitoring has never been greater. Drone-based radar mapping offers unparalleled access to hazardous and remote areas, enabling authorities and researchers to collect vital data without risking human lives. This capability is particularly valuable for preemptive avalanche detection and timely evacuation, reducing casualties and economic losses in affected communities. The combination of high-resolution imaging and advanced analytics further enhances the predictive accuracy of these systems, making them indispensable tools for modern avalanche management strategies.

Another key driver of market expansion is the rapid advancement of radar and sensor technologies integrated into UAV platforms. Innovations such as synthetic aperture radar (SAR), ground-penetrating radar (GPR), and LiDAR have significantly improved the precision and reliability of avalanche mapping. These technologies allow for detailed snowpack analysis, subsurface imaging, and real-time data transmission, which are critical for both immediate rescue operations and long-term research. The scalability and flexibility of drone-based systems also enable widespread deployment across various terrains and weather conditions, overcoming the limitations of traditional ground-based or manned aerial surveys. As a result, government agencies, research institutes, and emergency response teams are increasingly investing in drone-based radar solutions to strengthen their avalanche preparedness and response capabilities.

A third major factor contributing to the growth of the drone-based avalanche radar mapping market is the increasing collaboration between public and private sectors. Governments across North America, Europe, and Asia Pacific are implementing stringent safety regulations and investing in advanced monitoring infrastructure to protect both residents and tourists in high-risk regions. At the same time, private companies and commercial operators are developing specialized drone platforms and analytics software tailored for avalanche applications. This synergy is fostering innovation, driving down costs, and expanding the accessibility of drone-based radar mapping solutions. Additionally, the availability of dedicated services and training programs is accelerating the adoption of these technologies among emergency response teams and mountain rescue organizations, further propelling market growth.

From a regional perspective, Europe currently dominates the drone-based avalanche radar mapping market, accounting for over 38% of the global revenue in 2024. This leadership is attributed to the continent’s extensive mountain ranges, well-established ski tourism industry, and proactive government initiatives aimed at disaster risk reduction. North America follows closely, driven by significant investments in technological innovation and a strong focus on public safety in the Rockies and other snow-prone regions. Meanwhile, the Asia Pacific region is emerging as a high-growth market, supported by increasing awareness of avalanche risks in the Himalayas and growing investments in advanced UAV technologies. Other regions, including Latin America and the Middle East & Africa, are gradually recognizing the potential of drone-based radar mapping for disaster management and research, setting the stage for future market expansion.

for English see below

-br/- -/br- Datenbeschrieb -br/- -/br- Dieser Datensatz enthält die Umrisse der 11'120 Lawinen die aus schwarzweiss Luftbildern, welche zwischen dem 25.2.1999 und dem 1.3.1999 aufgenommen wurden, kartiert wurden. Die Lawinenumrisse haben verschiedene Attribute welche im beigelegten Beispielschlüssel beschrieben sind (Beispielschluessel_1999_d.pdf). Es gibt drei Shapefiles: * avalanches1999_endversion1.shp: die kartierten Lawinen (für Attribute siehe Beispielschlüssel!) * area_images_1999.shp: Fläche die durch die Luftbilder abgedeckt wurde * clouds_1999.shp: grobe Umrisse der Wolken in den Bildern Bildverfügbarkeit: Die entzerrten Luftbilder können von der Swisstopo einzeln über den Downloadlink heruntergeladen werden (herzlichen Dank an Holger Heisig für die Prozessierung und ans BAFU für die Finanzierung der Prozessierung!!). Über "Erweiterte Werkzeuge"/ "Datei importieren" können die Bilder nach hereinziehen des Orthofotolinks direkt im map.geo.admin.ch angezeigt werden. Weiterführende Litertaur: Details zu den Luftbildern und zur Kartierung, sowie eine kleine Analyse und Empfehlungen zur Verwendung der Daten finden sich unter - FAN Publikation (Info folgt) - Dal, F. J., Hafner, E. D., Peters, T., Narnhofer, D., Caye Daudt, R., Heisig, H., & Bühler, Y. (2024). Automated snow avalanche mapping with deep learning in aerial imagery from the extreme avalanche winter of 1999. In K. Gisnås, P. Gauer, H. Dahle, M. Eckerstorfer, A. Mannberg, & K. Müller (Eds.), Proceedings of the international Snow Science Workshop 2024 (pp. 1264-1271). Norwegian Geotechnical Institute. - Hafner, E. D., Techel, F., Heisig, H., Dal, J. F., & Bühler, Y. (2024). Remotely sensed avalanche activity during three extreme avalanche periods in Switzerland. In K. Gisnås, P. Gauer, H. Dahle, M. Eckerstorfer, A. Mannberg, & K. Müller (Eds.), Proceedings of the international Snow Science Workshop 2024 (pp. 1222-1229). Norwegian Geotechnical Institute.

-br/- -/br- Data description -br/- -/br- This dataset contains the outlines of 11'120 avalanches mapped from panchromatic aerial imagery taken between February 25, 1999 and March 1, 1999. The avalanche outlines have various attributes which are described in the attached example key (ExampleKey_AvalMapping_1999_e.pdf). There are three shapefiles: * avalanches1999_endversion1.shp: the mapped avalanches (for attributes see example key!) area_images_1999.shp: Area covered by the aerial images clouds_1999.shp: rough outlines of the clouds in the images Image availability: The rectified aerial images can be downloaded individually from Swisstopo via the download link (many thanks to Holger Heisig for processing and to BAFU for financing the processing!!). The images can be displayed directly in map.geo.admin.ch via “Advanced tools”/“Import file” after dragging in the orthophoto link. Further Reading: Details on the aerial images and mapping, as well as a brief analysis and tips on using the data can be found at - FAN Publication (info to follow) - Dal, F. J., Hafner, E. D., Peters, T., Narnhofer, D., Caye Daudt, R., Heisig, H., & Bühler, Y. (2024). Automated snow avalanche mapping with deep learning in aerial imagery from the extreme avalanche winter of 1999. In K. Gisnås, P. Gauer, H. Dahle, M. Eckerstorfer, A. Mannberg, & K. Müller (Eds.), Proceedings of the international Snow Science Workshop 2024 (pp. 1264-1271). Norwegian Geotechnical Institute. - Hafner, E. D., Techel, F., Heisig, H., Dal, J. F., & Bühler, Y. (2024). Remotely sensed avalanche activity during three extreme avalanche periods in Switzerland. In K. Gisnås, P. Gauer, H. Dahle, M. Eckerstorfer, A. Mannberg, & K. Müller (Eds.), Proceedings of the international Snow Science Workshop 2024 (pp. 1222-1229). Norwegian Geotechnical Institute.

The Charter brings together the census of 793 avalanches, specifying their geographical, morphological and temporal characterization. The Historical Map of Avalanches contains the graphic representation of the avalanche events recorded by the station commands of the Abruzzo Regional Command Forestry Corps in the period of time between 1957 and 2013. The map cannot be understood as a forecast or evaluation of possible avalanche events, but only as a simple log of avalanche events that have occurred. The Historical Map of the Avalanches was created for the sole purpose of studying and supporting the Civil Protection structure, it does not include aspects such as return times and does not contain assessments of the specific characteristics of the recorded events. This document is in fact only a summary of the facts known to the Civil Protection structure at the date of its publication, therefore it does not contain any predictions on how and where avalanches can occur. This study was approved by D.G.R. n.170 of 17 March 2014.

Avalanches are a mass movement of snow and ice down a hillside. They occur when unique circumstances of climate and topographic factors come together. This maps shows major avalanches beginning with the Rogers Pass avalanche in 1906 and extending to the 1999 avalanche in Kangiqsualujjuaq, Quebec.

BGC Engineering Inc. (BGC) was retained by Metro Vancouver to complete a desktop inventory and characterization of geohazards (landslide, riverine and coastal inundation, and snow avalanches) with the potential to affect key parcels in Metro Vancouver’s Electoral Area A. This is Phase 1 of a two-phase project to characterize geohazards and translate results into technical and policy maps for use in the review of building and land development permit applications. The current work is based on new landslide and snow avalanche mapping and existing geohazard information compiled from published reports and geoscience/engineering reports held by Metro Vancouver. The deliverables for this project are several pdf maps and the supporting spatial database (geographical information system – GIS). These deliverables provide a starting point and structure to update and refine results once further information becomes available through more detailed assessments.Last Updated - March 30, 2022Electoral Area A Geohazard Mapping Report - Phase 1: Geohazards Inventory and Methodology: https://metrovancouver.org/boards/ElectoralArea/EA_2022-Apr-7-ADD-5.1.pdf

On May 25, 2014, a rain-on-snow induced rock avalanche occurred in the West Salt Creek Valley on the northern flank of Grand Mesa in western Colorado. The avalanche mobilized from a preexisting rock slide and traveled 4.6 km down the confined valley, killing 3 people. The avalanche was rare for the contiguous U.S. because of its large size (54.5 Mm3) and long travel distance. To understand the avalanche failure sequence, mechanisms, and mobility, we mapped landslide structures, geology, and ponds at 1:1000-scale. We used high-resolution, Unmanned Aircraft System (UAS) imagery from July 2014 as a base for our field mapping. Herein, we present the map data and UAS imagery. The data accompany an interpretive paper published in the journal Geosphere. The full citation for this interpretive journal paper is: Coe, J.A., Baum, R.L., Allstadt, K.E., Kochevar, B.F., Schmitt, R.G., Morgan, M.L., White, J.L., Stratton, B. Hayashi, T.A., and Kean, J.W., 2016, Rock avalanche dynamics revealed by large-scale field mapping and seismic signals at a highly mobile avalanche in the West Salt Creek Valley, western Colorado: Geosphere, v. 12, no. 2, p. 607-631, doi:10.1130/GES01265.1

The service dynamically produces the map of the Historical Avalanche Map, the map contains the graphic representation of the avalanche events recorded by the station commands of the Forestry Corps Regional Command of Abruzzo in the period of time between 1957 and 2013. The Historical Map of the Avalanches was created for the sole purpose of studying and supporting the Civil Protection structure, it does not contemplate aspects such as, for example, return times and does not contain evaluations on the specific characteristics of the surveyed events. This document is in fact only a summary of the facts known to the Civil Protection structure at the date of its publication, therefore it does not contain any predictions on how and where avalanches can occur. This study was approved by D.G.R. n.170 of 17 March 2014.

This dataset contains the output and reference data published in the paper "Automated snow avalanche release area delineation - validation of existing algorithms and proposition of a new object-based approach for large scale hazard indication mapping" Yves Bühler, Daniel von Rickenbach, Andreas Stoffel, Stefan Margreth, Lukas Stoffel, Marc Christen (2018) Natural Hazards And Earth System Sciences. Abstract: Snow avalanche hazard is threatening people and infrastructure in all alpine regions with seasonal or permanent snow cover around the globe. Coping with this hazard is a big challenge and during the past centuries, different strategies were developed. Today, in Switzerland, experienced avalanche engineers produce hazard maps with a very high reliability based on avalanche cadastre information, terrain analysis, climatological datasets and numerical modelling of the flow dynamics for selected avalanche tracks that might affect settlements. However, for regions outside the considered settlement areas such area-wide hazard maps are not available mainly because of the too high cost, in Switzerland and in most mountain regions around the world. Therefore, hazard indication maps, even though they are less reliable and less detailed, are often the only spatial planning tool available. To produce meaningful and cost-effective avalanche hazard indication maps over large regions (regional to national scale), automated release area delineation has to be combined with volume estimations and state-of-the-art numerical avalanche simulations. In this paper we validate existing potential release area (PRA) delineation algorithms, published in peer-reviewed journals, that are based on digital terrain models and their derivatives such as slope angle, aspect, roughness and curvature. For validation, we apply avalanche cadastre data from three different ski resorts in the vicinity of Davos, Switzerland, where experienced ski-patrol staff mapped most avalanches in detail since many years. After calculating the best fit input parameters for every tested algorithm, we compare their performance based on the reference datasets. Because all tested algorithms do not provide meaningful delineation between individual potential release areas (PRA), we propose a new algorithm based on object-based image analysis (OBIA). In combination with an automatic procedure to estimate the average release depth (d0), defining the avalanche release volume, this algorithm enables the numerical simulation of thousands of avalanches over large regions applying the well-established avalanche dynamics model RAMMS. We demonstrate this for the region of Davos for two hazard scenarios, frequent (10 – 30 years return period) and extreme (100 – 300 years return period). This approach opens the door for large scale avalanche hazard indication mapping in all regions where high quality and resolution digital terrain models and snow data are available.

The avalanche risk areas have been mapped. These elements mean the areas at risk of avalanches that may affect the elements at risk, present in the area, indicated by the Civil Protection Service of the Liguria Region. The paper has been approved with DGR no. 1343 of 12/28/2022. The zoning was obtained considering the elements of the Probable Location Map of the avalanches (CLPV) in topological overlay with the areal and linear elements at risk. For precautionary reasons, a buffer of 20 m was applied to the elements at risk. - Year 2022 - Entire regional coverage - sc:1:25000 - S.Projection: Gauss Boaga - West Zone

Outlines of 6'041 avalanches mapped from SPOT6 satellite data over the Swiss Alps on 16 January 2019. The dataset was acquired following a period with very high avalanche danger. The outlines have different attributes described in the data example key (ExampleKey_AvalMapping16012019.pdf) The generation of the data is described in: Bühler, Y., E. D. Hafner, B. Zweifel, M. Zesiger, and H. Heisig (2019), Where are the avalanches? Rapid SPOT6 satellite data acquisition to map an extreme avalanche period over the Swiss Alps, The Cryosphere, 13(12), 3225-3238, doi:10.5194/tc-13-3225-2019. The data was comprehensivly validated in a subset area in Hafner, E.D.; Techel, F.; Leinss, S.; Bühler, Y., 2021: Mapping avalanches with satellites - evaluation of performance and completeness. Cryosphere, 15, 2: 983-1004. doi: 10.5194/tc-15-983-2021

It is important to be clear about what ATES is applied to, because the scale at which it is applied could affect the category outcome. When an ATES assessment is done of a catchment or mountain range it is likely that the area has in it a mixture of simple, challenging and complex. The finer the scale used, the more definite things will be. When assessing a large area you should think about what sort of user goes there and the degree of use. If a lot of people use a specific place then this should be looked at separately. As an example a mountain range may generally be ‘challenging’ but contain areas of ‘complex’. It still meets the definition of ‘challenging’ because people have options for avoiding avalanche paths. If people are using a particular valley in the range where there is no option for avoiding avalanche terrain then that place is ‘complex’.ATES assessments of the New Zealand back country will occur over a period of time. The initial places done for visitor information should be popular DOC tracks in avalanche terrain and the more heavily used back country areas. Initially many of these assessments will be done as larger scale assessments of catchments and ranges in order to give visitors a general indication of the likely ATES class contained in that area. If other groups and organisations have a need for more detailed analysis to work out where they wish to operate, they will need to take these larger areas and split them into smaller blocks. This information can then be incorporated into information that DOC and the MSC supply to visitors. As guidebooks are written or revised it would be good if they could include the ATES classifications of the routes and trips in them. Assessing the terrain:ATES assessments should be done by a small group of people who are familiar with the terrain. At least one person in that group needs to have the stage 2 avalanche qualification. When the assessment is done an assesment form needs to be filled in for each area being assessed. Displaying the results:An ATES assessment can be displayed either through marking the classifications onto a map or by the use of a list. When putting ATES assessments onto maps this should be done in a GIS system with the simple terrain in green, challenging in blue and complex in black. Attributes for ATES shape files need to have name of the shape and Class in them. Class data needs to be 1 or 2 or 3.If the ATES assessment is being done as a text list then the colours should be used if possible either through the lists of each terrain class being in the appropriate colour or through the use of a coloured header bar.SimpleChallengingComplexAoraki Mount Cook VillageUpper Tasman GlacierGrand PlateauTasman Valley FloorMueller GlacierTrack to Mueller HutWhen preparing pamphlets the appropriate terrain class should be used in the text and reference made to the ATES system and where to get more information on it. The use of the terrain class on warning signs should also be encouraged.Public Information model:The following table is the public information model. This information will need to go into any web sites giving information on ATESand into ATES pamphlets and visitor centre information along with the accompanying advice on the amount of experience needed.DescriptionClassTerrain CriteriaSimple1Exposure to low angle or primarily forested terrain. Some forest openings may involve the run-out zones of infrequent avalanches. Many options to reduce or eliminate exposure. No glacier travel.Challenging2Exposure to well defined avalanche paths, starting zones or terrain traps; options exist to reduce or eliminate exposure with careful route-finding. Glacier travel is straightforward but crevasse hazards may exist.Complex3Exposure to multiple overlapping avalanche paths or large expanses of steep, open terrain; multiple avalanche starting zones and terrain traps below; minimal options to reduce exposure. Complicated glacier travel with extensive crevasse bands or icefalls.

the Avalanche Phenomena Location Map (CLPA)describes areas where avalanches have occurred in the past and are represented by their extreme limits reached

The Map of Location of the Phenomenas of Avalanche is a descriptive map of observed or historical phenomena, whose purpose is to inform and sensitise the population about the existence, in mountain territory, of areas where avalanches have actually occurred in the past, represented by the extreme limits reached. The CLPA is an informative document that has no regulatory value and has no forward-looking analysis of the institution. The CLPA is designed to inform all those interested in the existence of avalanches in a given region. A technical document, it is particularly aimed at Mayors and administrative or technical departments concerned with the problems of natural hazards in mountain areas.

The CLPA includes a mapping document at 1/25 000 supplemented by MSDS. The CLPA map represents three information themes: the result of an aerial photo study (photo-interpretation and field analysis); the proceeds of a collection of testimonies by investigation; and, for information purposes, fixed protective devices

Due diligence areas for potential avalanche hazards are a GIS-generated nationwide dataset that provides a rough overview of areas that could potentially be avalanche exposed. The due diligence maps for avalanches that have been laid with a new method in 2023. These are developed by the Norwegian Geotechnical Institute (NGI) and are managed by NVE.

Creation of the map of avalanche danger areas (CLPV), for causes essentially linked to static factors. The mapping is based, as indicated in the aforementioned directive of 12/08/2019 (page 7 of the Official Gazette of 2 October 2019), on the analysis of the territory through photo-interpretation and on the topological overlay between the following information levels, relating to the aforementioned static factors: - Map of steepness (in particular, inclinations between 27 and 55 degrees were considered) - Map of land use, indicating the type of vegetation - Hydrographic network with channels, basins and sub-basins - Morphology (in particular gullies and crests) - Altitude bands (considering only the altitudes historically affected in Liguria by the problem in question, i.e. those above 800 m for inland mountain areas and 1000 m for coastal areas - year 2022 - entire regional coverage - sc:1:25000 - S. Projection: Gauss Boaga - West Zone

The avalanche risk areas have been mapped. These elements mean the areas at risk of avalanches that may affect the elements at risk, present in the area, indicated by the Civil Protection Service of the Liguria Region. The paper has been approved with DGR no. 1343 of 12/28/2022. The zoning was obtained considering the elements of the Probable Location Map of the avalanches (CLPV) in topological overlay with the areal and linear elements at risk. For precautionary reasons, a buffer of 20 m was applied to the elements at risk. - Year 2022 - Entire regional coverage - sc:1:25000 - S.Projection: Gauss Boaga - West Zone

The effects of climate change have the potential to impact slope stability. Negative impacts are expected to be greatest at high northerly latitudes where degradation of permafrost in rock and soil, debuttressing of slopes as a result of glacial retreat, and changes in ocean ice-cover are likely to increase the susceptibility of slopes to landslides. In the United States, the greatest increases in air temperature and precipitation are expected to occur in Alaska. In order to assess the impact that these environmental changes will have on landslide size (magnitude), mobility, and frequency, inventories of historical landslides are needed. These inventories provide baseline data that can be used to identify changes between historical and future landslide magnitude, mobility, and frequency. This data release presents GIS and attribute data for an inventory of rock avalanches in a 5000 sq. km area of western Glacier Bay National Park and Preserve, Alaska. We created the inventory from 30 m resolution Landsat imagery acquired from June 1984 to September 2016. For each calendar year, we visually examined a minimum of one Landsat image obtained between the months of May and October. We examined a total of 104 Landsat images. The contrast between the spectral signatures of freshly exposed rock avalanche source areas and deposits and surrounding, undisturbed snow and ice is typically significant enough to detect surficial changes. We identified and mapped rock avalanches by locating areas with 1) high contrast compared to surrounding snow and ice, 2) different spectral signatures between successive Landsat images, and 3) lobate forms typical of rock-avalanche deposits. Using these criteria, we mapped a total of 24 rock avalanches ranging in size from 0.1 to 22 km2. Attribute data for each rock avalanche includes: a date, or range in possible dates, of occurrence; the name of the Landsat image(s) used to identify and map the avalanche; the total area covered by the rock avalanche (including the source area and deposit); the maximum travel distance measured along a curvilinear centerline (L); and the change in elevation between the start and end points of the centerline (H). We also include a table containing a list of all the Landsat images examined. We acknowledge that our mapped polygons will be different, and less accurate, than polygons that could be mapped from higher-resolution satellite, aerial, and hand-held imagery. We specifically chose not to use high resolution imagery because we desired a long-term historical inventory that was unbiased by changes in image resolution. Eventually, new mapping should be done to create an inventory that fully utilizes recently available high-resolution imagery. Data included in this release form the basis of an interpretive paper available in the conference proceedings of the 3rd North American Symposium on Landslides held in Roanoke, Virginia in June, 2017.

Avalanche paths of the tri-canyon (Millcreek, Big Cottonwood, Little Cottonwood) area. Avalanche paths were identified and digitized from aerial photography and 7.5 minute USGS quadrangles. Data were prepared by Utah AGRC staff for the Salt Lake County Wasatch Canyons Master Plan and published in September 1989.

The avalanche risk refers to the interaction between the phenomena of instability of the snowpack which can send snow masses downstream and the anthropic mountain territory, generating very serious damage.