| 14 Jul 2026
How exposed is a mountain road to snow avalanches? A corridor-scale assessment in the southern Andes
Abstract. The International Route 115-CH (Pehuenche Pass, ~36° S, Chile) is a key Andean border crossing that is closed repeatedly each winter by snow and adverse-weather hazard. Yet no calibrated, corridor-scale assessment of avalanche exposure exists for any mountain road in the southern Andes, where systematic avalanche records are largely absent. We combine back-analysis of documented avalanches with corridor-wide simulation in the open-source AvaFrame model (com1DFA). After calibrating friction on two documented paths, we simulate 208 release areas along the 61 km corridor under three snow-depth scenarios. Simulated avalanches reach up to 40 % of the corridor. Of all road crossings, 77 % exceed the 30 kPa vehicle-damage threshold and 41 % exceed the 100 kPa vehicle-destruction threshold, and avalanches typically arrive within a minute of release (median 25 s), leaving little time for evacuation. Mapping these arrival times, the first such analysis for the route, reveals the few segments where preventive closure can substitute for permanent structural protection. Exposure is highly non-uniform: six hot-spot segments, about 7 km (11 %) of the route, concentrate the highest path convergence and define where mitigation would most reduce collective risk. Key limitations are the friction calibration anchored on two documented paths, the 12.5 m terrain model, and the exposure-based framing: results are conditional on avalanche release and do not represent annualized risk. However, using only open-source tools and public data, the workflow is reproducible and transferable to other data-scarce mountain corridors in the Andes and beyond.
Competing interests: Felix Oesterle is one of the developers of the open-source AvaFrame simulation framework used in this study, as declared in the competing interests section of the manuscript. No other competing interests are present.
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