Infrasound detection of avalanches: operational experience from 26 systems in Canada, Switzerland and Norway - individual and multi-array based approaches

During the winter seasons 2019-2020 and 2020-2021 as well as during the current season 26 avalanche infrasound detection systems (IDA®) were used by Parks Canada, the Norwegian Road Administration and Swiss cantons as support for operational decision making to minimize avalanche risk. In this period, more than 800 controlled avalanches and 2700 natural avalanches were detected and delivered in near-real-time to avalanche teams.

Operational efficiency of the Trans-Canada Highway (BC) in the winter months is highly dependent on effective avalanche control. Here the goal of infrasound technology is to provide the Glacier National Park avalanche control team with information on avalanche activity in specific avalanche sectors and paths to reduce avalanche related road closure times. Infrasound technology has also been successfully applied in sparsely vegetated terrain at high altitudes and latitudes such as in Norway, where the Norwegian Public Roads Administration operates infrasound systems along remote road sections where visual observations are difficult to gather. Experiences from regional avalanche forecasting teams in Switzerland where multiple arrays are distributed over a larger area are also presented.

In this work we want to give an overview of results obtained from the use of infrasound technology with particular focus on advantages and limitations encountered in various operational contexts. Recent results of ongoing developments such as multi array processing are also presented.