Avalanche Hazard
Evaluation
 |
|
Avalanches
do Happen
|
1.
Could the Terrain Avalanche?
· Is the slope steep enough? (30
to 45 degrees)
· What is the nature of the terrain?
(gullies, open, thin forest)
· Slope configuration? (concave
or convex)
· What is the orientation of the
slope? (lee or sun effected)
2.
Could the snowpack fail?
· What is the avalanche forecast?
· Any signs of recent avalanche activity?
· Has there been recent snowfall? (30cm or more)
· Is there a slab? (cohesive layer, 30cm or larger)
· Is there a weak layer? (is it below the slab, moderate to easy shear
strength)
·
Is there a sliding surface?
· How do these layers interact?
3.
Is the weather increasing the avalanche hazard?
· Is the wind loading slopes? (26kph
or more)
· Is there current precipitation? (Rain or snowfall at a rate of 3cm
per hour)
· Is there a temperature change? (Temperature increase during a storm,
rapid temperature rise,
above 0 C
for an extended
time, prolonged cold after a storm)
· Has the sun effected the slope? (Bright
sunny day )
4.
What are the consequences of an avalanche ?
· Are there terrain traps? (Restricted runout zone)
· Are there falling hazards? (Cliffs, length of runout)
· Will it be a large avalanche? (Thick slab or a large area)
· Are there obstacles in the runout zone? (Trees, rocks etc)