Avalanches are natural events (or hazards due to their destructive capacity) that are characterized by movement of very large snow mass over a slope. Extremely large quantity of snow moves very rapidly over steep slopes and causes great deal of destruction to forests, infrastructure, houses, etc. Two characteristics are necessary for avalanches to take place, a large quantity of snow and a steep slope. These characteristics are interrelated. Very steep slope will not be able to hold large quantity of snow, as it will move down the slope before accumulating. Gentle slopes, on the other hand, will not be able to provide the acceleration that is required to be called an avalanche. Generally, it has been observed that slopes between 35 to 45 degrees are very conducive to avalanches. Cascade mountains, Alps mountains and parts of Canada are very conducive to avalanche occurrence.
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