Understanding the dynamics of an avalanche

Professor Jim McElwaine of the Department of Earth Sciences talks about new research, published in the Journal of Geophysical Research: Earth Surface , which has given some of the first detailed measurements of what takes place inside an avalanche. Tell us a bit about the research? The aim of the project was to understand what processes are taking place inside an avalanche as it travels down a mountain. The internal processes of avalanches are difficult to measure as they are often obscured by the powder cloud of snow that is thrown up during the event. In this study the research group, which included the Swiss Federal Institute for Snow and Avalanche Research, used explosives to artificially trigger five avalanches in Switzerland's Vallée de la Sionne. We then used a mix of innovative radar technology, pylon-mounted sensors and video to get the best look yet at what is taking place inside an avalanche. Artificially-triggered avalanches were necessary as naturally-caused avalanches are unpredictable and hard to observe. How did you measure what was taking place inside an avalanche? Past studies have used Doppler radar to detect the speed of an avalanche under the powder cloud.