In snow, acoustic emissions originate from the breaking of bonds between snow crystals and the formation of cracks. Previous research has shown that acoustic signals emanate from a natural snowpack. The relation between these signals and the stability of the snowpack has thus far remained
elusive. Studies on other hazardous gravitational processes suggest that damage accumulation precedes major failure. If increased cracking activity could be detected in snow this might be used for avalanche prediction. We report on the development of a seismic sensor array to continuously
monitor acoustic emissions in an avalanche start zone. During three winters, over 1400 sensor days of continuous acoustic data were collected. With the aid of automatic cameras and a microphone the main types of background noise were identified. Seismic signals generated by avalanches were
also identified. Spectrograms from seismic signals generated by avalanches exhibit a unique triangular shape unlike any source of background noise, suggesting that automatic detection and classification of events is possible. Furthermore, discriminating between loose-snow and snow-slab avalanches
is possible. Thus far we have not identified precursor events for natural dry-snow slab avalanche release. Detailed investigation of one dry-snow slab avalanche showed that signals observed prior to the release originated from background noise or small loose-snow avalanches.
The Journal of Glaciology is published six times per year. It accepts submissions from any discipline related to the study of snow and ice. All articles are peer reviewed. The Journal is included in the ISI Science Citation Index.