NEET BIOLOGY

Detailed explanation-1: -A snow avalanche begins when an unstable mass of snow breaks away from a slope. The snow picks up speed as it moves downhill, producing a river of snow and a cloud of icy particles that rises high into the air. The moving mass picks up even more snow as it rushes downhill.

Detailed explanation-2: -An avalanche occurs when a layer of snow collapses and slides downhill. Avalanches are caused by four factors: a steep slope, snow cover, a weak layer in the snow cover and a trigger. Roads and railway tracks may be rerouted to reduce risks. Safe avalanches may be triggered in dangerous snow packs.

Detailed explanation-3: -Snow avalanches are a well-known hazard type and are defined as a sudden release of snow masses and ice on slopes, sometimes containing portion of rocks, soil, and vegetation; and by definition the downhill trajectory exceeds 50 m (Wilhelm, 1975).

Detailed explanation-4: -The snowpack on flatter slopes requires more force to move. Avalanche risk is at its greatest 24 hours following a snowfall of 12 inches or more. Avalanches can reach speeds of 80 mph within about 5 seconds. The deadliest avalanche in American history was due to a train wreck in 1910.