Knowra Avalanche Avalanche An avalanche is a rapid downslope movement of snow, ice, rock, or debris under gravity. Snow avalanches range from loose surface slides to large slab failures.
Snowpack : A layered accumulation of snow on the ground, shaped by successive storms and changing weather. Avalanches often fracture along weak layers within this layered structure.
Avalanche forecasting : The assessment and communication of avalanche likelihood, size, and danger for a region and time period. Forecasters combine snowpack observations, weather, and terrain to estimate regional danger.
Avalanche burial : The entrapment of a person beneath snow or debris carried by an avalanche. Burial can obstruct breathing and cause fatal asphyxia within minutes.
White Friday avalanches : A series of World War I avalanches in the Alps in December 1916 that killed thousands of soldiers. These catastrophic releases show how artillery and heavy snowfall can combine with mountain terrain.
Weak layer : A fragile layer in a snowpack that fractures or collapses beneath stronger overlying snow. Failure in this layer can release an entire slab above it.
Avalanche danger scale : A standardized scale communicating avalanche danger, including likelihood, size, and distribution. The scale translates forecast conditions into comparable public danger levels.
Avalanche path : A route through which avalanches repeatedly travel from release area to deposition zone. Repeated paths shape where damage occurs and where structures face recurring risk.
Huascarán avalanche : The 1970 debris avalanche from Mount Huascarán in Peru, triggered by the Ancash earthquake. It illustrates how a rock-and-ice collapse can transform into a fast-moving debris flow.
Slab avalanche : An avalanche in which a cohesive plate of snow breaks away along a weak layer. This common destructive form begins with a connected snow slab breaking loose.
Avalanche terrain : Mountain terrain where avalanches can start, travel, or deposit snow and debris. Recognizing start zones, tracks, and runouts helps people avoid exposure.
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