 INTRODUCTION
TYPES
OF AVALANCHE
THE
MECHANISM OF AVALANCHE RELEASE
FORECASTING
SNOW AVALANCHES
AVALANCHE
CONTROL TECHNIQUES
AVALANCHE
HAZARD RATINGS
AVALANCHE
TRAINING FOR DOGS
INFO
ON THE PAGE OWNERS
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TYPES
OF AVALANCHE...
Slab avalanches originate in snow with
sufficient internal cohesion to enable a snow layer, or layers, to react
mechanically as a single entity. The degree of this required cohesion may
range from very slight in fresh, new snow (soft slab) to very high in hard,
winddrifted snow (hard slab), according to circumstances of layer attachment
to the external environment. A slab avalanche breaks free along a characteristic
fracture line, a sharp division of sliding from stable snow whose face
stands perpendicular to the slope. The entire surface of unstable snow
is set in motion at the same time. A slab release may take place across
an entire mountainside, with the fracture racing from slope to slope to
release adjacent or even distant slide paths. The mechanical conditions
leading to slab avalanche formation are found in a wide variety of snow
types, both new and old, dry and wet. They may be induced by the nature
of snow deposition (wind drifting is the prime agent of slab formation),,
or by internal metamorphism.
Referring
to the above picture: The fracture line of a slab avalanche,
showing the sharp boundary between the stable snow
and that which slid away to the left. Note blocks of the hard slab resting
on the sliding surface.
Slab avalanches are often dangerous
and unpredictable in behavior. Providing most of the winter avalanche hazard,
they axe the primary object of avalanche defense and control measures.
 
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Picture Gallery
In this section, you will
get to see pictures of avalanches happening worldwide...dated from the
1900...
Maps of avalanche-affected
areas
Click on the globe to see
frequently hit places...
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