Patterns of recreational backcountry usage - analyzing data from social media mountaineering networks and avalanche statistics

2 Bergportal GmbH ABSTRACT: Most avalanche accidents involving people occur during recreational activities. So far, risk analysis studies mostly rely on accident statistics without considering exposure (or the elements at risk), i.e. how many, when and where people are recreating. As backcountry usage data is scarce, we explored condition reports on social media mountaineering networks. We compared more than 15'000 reports posted on bergportal.ch and camptocamp.org with accident data. We noted similar patterns in avalanche accident data and user data with respect to demographics of recreationists. Considerably more accidents and activities were recorded on weekend-days rather than weekdays and during fine rather than poor weather conditions. On days with fine weather and lower avalanche hazard more challenging backcountry tours were undertaken. While backcountry touring accidents were equally frequent at danger levels 2 and 3, usage frequencies were twice as high on days with danger level 2. The odds of being involved in an avalanche accident increased by a factor of 5 from danger level 1 to 2, and a factor of 2 between higher danger levels.