But now, engineers and scientists from several British universities have devised a new, radar-based imaging system that can see inside of snow banks and produce 3-D images of how snow moves deep inside them.
While the technology isn't yet capable of forecasting avalanches, the researchers say that it will make computer modeling of avalanches more accurate and eventually could aid in devising more resilient defenses for towns, buildings, roads and railways.
"It's not possible to predict precisely when avalanches will happen, but our radar imaging system aids understanding of how they behave when they do occur," said University College London professor Paul Brennan, the project's leader, in a press release.
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"By penetrating the powder cloud, it can observe the nature and direction of the flow of the 90 percent of snow that would otherwise remain invisible," he said.
The system uses an antenna to transmit radio waves and a receiver array to capture them as they reflect back from the snow.
The power and wavelength of the radio waves maximize their ability to penetrate into the snow as it moves. It has a 30-degree field of view, providing full coverage of an avalanche track. The scientists say that it offers greater sensitivity and higher resolution images than any other similar system previously developed.
The team, from University College London, Durham University and Sheffield University, worked in close collaboration with the Swiss Federal Institute for Snow and Avalanche Research.
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As this 2012 CBC article details, avalanches occur when a layer or layers of snow become disturbed, leading the top layer to become unstable. They can be set off by a variety of triggers, ranging from additional snowfall to a sudden, warming wind.
CBC says the folk belief that avalanches can be triggered by the human voice pretty much has been disproved.
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