Alaska Snow Avalanche Hazards Database

Wolken, G.J.Fischer, ElizabethHendricks, M.D.Wikstrom Jones, K.M.2026Alaska Snow Avalanche Hazards DatabasedataDigital Data SeriesDDS 26Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys7 p.https://doi.org/10.14509/32076Alaska Snow Avalanche Hazards Database, Digital Data Series 26, is a statewide geospatial archive that systematically stores, organizes, and shares snow avalanche hazard information. It is designed to hold standardized raster and vector layers describing snow and terrain conditions, potential release areas, simulated avalanche extents, and derived hazard indication data. The structure emphasizes repeatable, map-based workflows that can be applied consistently across regions and scales, from broad hazard indication assessments to path-specific analyses. Modular and updateable, the database can incorporate new avalanche datasets as they become available. Its primary goal is to serve as a centralized repository of snow avalanche hazard information that supports evidence-based decision-making for land-use planning, transportation, resource management, and risk-reduction efforts. These data and accompanying discussion are released as a DGGS Digital Data Series publication, and all publication components are available from the DGGS website at https://doi.org/10.14509/3207632076.The Alaska Snow Avalanche Hazards Database centralizes standardized data layers that describe snow and terrain conditions, potential release areas, and modeled avalanche extents for Alaska, where steep terrain, deep snowpacks, and exposed communities and transportation corridors make avalanches a recurring hazard. It supports evidence-based land-use planning, transportation, resource management, and risk-reduction decisions across avalanche-prone areas of the state, particularly where field-based hazard mapping is limited.The Alaska Snow Avalanche Hazards Database is not suitable for answering site-specific or legal questions and should only be used for regional- or community-scale purposes. Maps generated from the database should not be viewed at scales finer than those specified in the original data sources, and all limitations of the original publications apply to this database. >avalanche_hazard_deposition: Modeled depth of snow deposited by avalanches, in meters (m). Available for four scenarios: Frequent Historical (1981-2010), Rare Historical (1981-2010), Frequent Future, and Rare Future. Frequent scenarios have an estimated return period of less than 30 years, and rare scenarios have an estimated return period between 30 and 300 years. Historical scenarios represent climate conditions from 1981 to 2010, and future scenarios represent projected future climate conditions. >avalanche_hazard_max_pressure: Modeled maximum impact pressure of avalanches, in kilopascals (kPa). Available for four scenarios: Frequent Historical (1981-2010), Rare Historical (1981-2010), Frequent Future, and Rare Future. Frequent scenarios have an estimated return period of less than 30 years, and rare scenarios have an estimated return period between 30 and 300 years. Historical scenarios represent climate conditions from 1981 to 2010, and future scenarios represent projected future climate conditions. >avalanche_hazard_extent: A simple extent of the modeled avalanche area. Available for four scenarios: Frequent Historical (1981-2010), Rare Historical (1981-2010), Frequent Future, and Rare Future. Frequent scenarios have an estimated return period of less than 30 years, and rare scenarios have an estimated return period between 30 and 300 years. Historical scenarios represent climate conditions from 1981 to 2010, and future scenarios represent projected future climate conditions.2026publication datePlannedIrregular-180.000000180.00000071.39202951.217293ISO 19115 Topic CategorygeoscientificInformationAlaska Division of Geological & Geophysical SurveysAvalancheClimateCoastalCoastal and RiverDatabaseDGGSEmergency PreparednessGeologicGeologic HazardsGeological ProcessGeologyGeomorphologyHazardsMethodsModelingMountainRemote SensingRepeat Data CollectionSlopeSlope InstabilitySnow AvalancheSnow DepthTopographyTransportationTransportation CorridorAlaska Division of Geological & Geophysical SurveysAdmiralty IslandAlaskaAlaska, State ofChilkat PassChilkoot PassHainesHaines HighwayHyderJuneauKlondike HighwaySkagwaySoutheast AlaskaWhite PassThis report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.Alaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical

3354 College Road

FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysPlease view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.This project was funded by the U.S. Geological Survey Alaska Climate Adaptation Science Center (Grant Number G21AC10867). We gratefully acknowledge the many avalanche safety practitioners and scientists who contributed their time and expertise to reviewing this work and informing the development of the Alaska Snow Avalanche Hazards Database. The views and conclusions contained in this publication are those of the authors and do not necessarily represent the opinions or policies of the U.S. Government. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Government. This report and database are submitted for publication with the understanding that the U.S. Government is authorized to reproduce and distribute reprints for governmental purposes.Wikstrom Jones, K.M.Wolken, G.J.Janes, MichaelWilbur, ChrisGlaus, JuliaBartelt, PerryChristen, Marc2023Assessing powder cloud impact on electrical transmission lines at Snowslide Creek avalanche path in Southeast Alaska (poster): International Snow Science Workshop, Bend, Oregon, October 8-13, 2023Poster and PresentationWikstrom Jones, K.M. and others, 2023Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheethttps://doi.org/10.14509/32167Wikstrom Jones, KatreenWolken, G.J.Janes, Michael2026From point to slope: Assessing weather station snow depth representativeness using lidar and geostatistics (poster): International Snow Science Workshop, Whistler, BC, Canada, September 28-Oct 2, 2026Poster and PresentationWikstrom Jones, Katreen and others, 2026Fairbanks, Alaska, United StatesAlaska Division of Geological & Geophysical Surveys1 sheethttps://doi.org/10.14509/32166The model outputs have not been calibrated or validated against observed avalanche events because Alaska lacks a long-term, spatially extensive avalanche incident database, so accuracy is untested and the results carry substantial uncertainty from coarse terrain, land cover, and downscaled climate inputs. The maps are best used as first-order, regional- to community-scale hazard indicators where field-based assessments are not feasible.All layers were produced with the same methods and a common grid resolution and merged into continuous maps, with only minor processing artifacts that have little effect on the final hazard layers.The database currently covers only parts of Alaska. It does not include observed avalanche events, some avalanche types (such as powder and wet-snow avalanches), or certain release mechanisms. Fine-scale terrain, weather, and land cover information is also limited. Additional regions and refined datasets will be added as they become available.Locations are based on a 10 m grid derived from the USGS 5 m IFSAR elevation model, so positional detail is limited to roughly that resolution, and coarser inputs such as 30 m land cover and 4 km climate data further reduce local precision. No formal horizontal accuracy assessment was performed, and the maps should not be used at scales finer than the original data sources support.Database deployment - The first iteration of the database focuses on regional, model-based hazard indication products for Southcentral and Southeast Alaska (roughly from the central Chugach Mountains to Alaska's southeastern border). The hazard map layers were produced following the methods of Buhler and others (2022) and used three main inputs. Terrain came from the USGS Alaska IFSAR digital elevation model, resampled from 5 m to 10 m. A forest mask from the 2016 National Land Cover Database identified protective evergreen forest, where avalanches could not start. Extreme snowfall was estimated from 1981-2010 reanalysis data, dynamically downscaled to 4 km with the Weather Research and Forecasting model and then to 10 m using a constant lapse rate. Potential release areas were mapped from terrain derivatives and the forest mask for Frequent (about 30-year) and Rare (about 300-year) scenarios. They were sorted into four size classes to set friction parameters, using area rather than release volume as a deviation from Buhler and others (2022). The RAMMS::LSHIM model was then run for each release area across four 30 km tiles. Avalanche extents were defined as areas with flow depth above 0.25 m and velocity above 1 m s^-1. Results were filtered to remove unrealistic low-elevation avalanches caused by land cover misclassification, and the tiles were merged into continuous hazard layers.2026rasterWeb Mercator0.00.000coordinate pair1010metersWGS84WGS 846378137298.257223563avalanche_hazard_depositionModeled depth of snow deposited by avalanches, in meters (m). Available for four scenarios: Frequent Historical (1981-2010), Rare Historical (1981-2010), Frequent Future, and Rare Future. Frequent scenarios have an estimated return period of less than 30 years, and rare scenarios have an estimated return period between 30 and 300 years. Historical scenarios represent climate conditions from 1981 to 2010, and future scenarios represent projected future climate conditions.this report, DGGS staffavalanche_hazard_depositionavalanche_hazard_max_pressureModeled maximum impact pressure of avalanches, in kilopascals (kPa). Available for four scenarios: Frequent Historical (1981-2010), Rare Historical (1981-2010), Frequent Future, and Rare Future. Frequent scenarios have an estimated return period of less than 30 years, and rare scenarios have an estimated return period between 30 and 300 years. Historical scenarios represent climate conditions from 1981 to 2010, and future scenarios represent projected future climate conditions.this report, DGGS staffavalanche_hazard_max_pressureavalanche_hazard_extentA simple extent of the modeled avalanche area. Available for four scenarios: Frequent Historical (1981-2010), Rare Historical (1981-2010), Frequent Future, and Rare Future. Frequent scenarios have an estimated return period of less than 30 years, and rare scenarios have an estimated return period between 30 and 300 years. Historical scenarios represent climate conditions from 1981 to 2010, and future scenarios represent projected future climate conditions.this report, DGGS staffavalanche_hazard_extentAlaska Division of Geological & Geophysical SurveysMetadata Managermailing and physical

3354 College Road

FairbanksAK99709-3707USA(907)451-5020(907)451-5050dggspubs@alaska.gov8 am to 4:30 pm, Monday through Friday, except State holidaysFGDC Content Standard for Digital Geospatial MetadataFGDC-STD-001-1998If the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the Alaska Department of Natural Resources or Division of Geological & Geophysical Surveys.https://dggs.alaska.gov/metadata/dggs.extdggs metadata extensions