June 19, 2013
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Kinds of Avalanches
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Snowpack
To get an avalanche, you need a steep slope plus unstable snow.
Recent avalanches indicate unstable snow.
On these days avoid steep slopes; however,
when the snow is stable you can ride on anything you want.
Learn how layers form in the snow. Watch the video to the right>>
How do we know when the snow is unstable?
Nature gives us lots of clues or red flags when the snowpack is unstable. Whumpfs or shooting cracks are a sign of unstable snow. Recent avalanches are the best clue of unstable snow.
If you see one avalanche, more are likely to occur.
This rider is ignoring mother nature's warning.
Getting stuck a lot?
Depth hoar otherwise known as rotten snow is a deadly weak layer. Getting stuck a lot is a good sign that the snowpack may be unstable.
In the above diagram, the buried weak layer has collapsed and the overlying slab layer has fractured and avalanched
.
Sometimes obvious clues are not present
We don't always see clues like
recent avalanches
, but weather plays a significant role. Learn to recognize when weather makes the snow unstable.
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Weather »
USFS National Avalanche Center