Statistical runout modeling of snow avalanches using GIS in Glacier National Park, Canada D. Delparte a, ⁎, B. Jamieson b, 1 , N. Waters c,2 a Department of Geography, University of Calgary, 2500 University Dr NW, Calgary, AB, Canada T2N 1N4 b Department of Civil Engineering and the Department of Geoscience, 2500 University Dr NW, University of Calgary, Calgary, AB, Canada T2N 1N4 c Department of Geography, George Mason University, 4400 University Drive MS 1E2, Fairfax, Virginia, 22030, United States abstract article info Article history: Received 20 September 2007 Accepted 28 July 2008 Keywords: Snow avalanches Hazard mapping Geographic Information Systems Digital terrain model Using models to estimate snow avalanche runout distance is useful for areas where there is a lack of historical avalanche observations and no obvious physical signs of avalanche activity. Along roadways, details of avalanche runout are often recorded; however, in Canada, backcountry areas typically used by recreationists may not have a recorded history of avalanche activity or runout distances. Knowledge of predicted runout extents mapped in Geographic Information Systems (GIS) has the potential to inform backcountry users on route selection and decision making pertaining to slopes for skiing, snowboarding, ice climbing and snowmobiling. The Rogers Pass area in Glacier National Park, British Columbia, Canada provides an ideal location for studying well documented avalanche paths that impact the Trans Canada Highway, as well as representing a backcountry area that is a popular ski touring destination in Canada. A statistical approach using the alpha–beta runout model, first developed in Norway, has been adapted for use in Rogers Pass. Topographic parameters from well-known avalanche paths along the Trans Canada Highway corridor, with a historical record of over 40 years, have been extracted with GIS and used to calibrate the alpha–beta runout model. This model is then applied to an avalanche path in the Glacier National Park backcountry. A high resolution Digital Elevation Model (DEM) was created for the study area using digital stereo photo- grammetry. A comparison of model calculations using the higher resolution dataset and a lower resolution dataset did not reveal any significant difference between the model parameters. © 2008 Elsevier B.V. All rights reserved. 1. Introduction Determining snow avalanche runout extent is an important consideration for mapping avalanche hazard for backcountry users, transportation corridors and other human infrastructure. The runout zone is the portion of the avalanche path where large avalanches begin to slow down and deposition of snow and entrained material occurs. The threshold for mapping runout in backcountry ski operations involves identifying a runout extent for a return period of less than 10 years (Canadian Avalanche Association, 2002). Runout zones can be identified through a combination of field observations, historical records, meteorological data and analysis of aerial photos and topographic maps for vegetative and geomorphic evidence (Canadian Avalanche Association, 2002; Mears, 1992; Weir, 2002). In areas where historical observations and field evidence are lacking, estimating avalanche extent may be difficult and runout models provide an option for estimating runout. Snow avalanche runout modeling is generally accomplished with statistical models, physically based models or a combination of the two approaches. The statistical models provide an estimate for runout along the centreline of the avalanche path and are limited in that they do not indicate the lateral extent of avalanches. In 2004 Parks Canada developed an Avalanche Terrain Exposure Scale (ATES) based upon terrain and land cover characteristics to identify avalanche susceptible areas in the backcountry (Statham et al., 2006). Using a defining set of terrain based criteria, avalanche professionals designate “simple”, “challenging” and “complex” ava- lanche terrain. Elements of determining the exposure scale rely upon the identification of runout. ATES is also used as part of the Avaluator trip planner that takes into account the current avalanche bulletin (Haegeli and McCammon, 2006). Varying levels of caution are recommended depending upon the level of avalanche danger and the type of terrain the user is travelling in. Runout models offer the potential for ATES-based runout mapping to aid backcountry users in reducing risk. Dynamic models are adept at indicating velocity and impact pressures along with avalanche runout and are especially suited for analysis where defence structures would be situated or impacts to Cold Regions Science and Technology 54 (2008) 183–192 ⁎ Corresponding author. Tel.: +1 403 220 5584; fax: +1 403 2826561. E-mail addresses: ddelparte@selkirk.ca (D. Delparte), bruce.jamieson@ucalgary.ca (B. Jamieson), nwaters@gmu.edu (N. Waters). 1 Tel.: +1 403 220 7479; fax: +1 403 282 7026. 2 Tel.: +1 703 993 4687; fax: +1 703 993 1216. 0165-232X/$ – see front matter © 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.coldregions.2008.07.006 Contents lists available at ScienceDirect Cold Regions Science and Technology journal homepage: www.elsevier.com/locate/coldregions