Avalanche Detection Using Infra-Sound Techniques

Makarand writes "Extremely sensitive 'micro-barometers' that measure changes in air pressure caused by infra-sound waves generated by nuclear explosions are used worldwide in nuclear test-ban monitoring systems. Now this same technology is being tested in Colorado, Utah, California and Montana for detecting avalanches using infra-sound techniques and extending the coverage of forecasts. An avalanche slide in addition to being audible to people nearby also generates infra-sounds -- very low frequency sound waves far below the threshold of human hearing -- that can be detected from many kilometres away by micro-barometers. Since the speed of sound is 10 times faster than the speed of an avalanche these detectors might be able to give people enough warning in advance to take cover."