1. At greater the snowfall rate the greater the _______ rate.
strain
Loose snow and soft slab avalanches should be expected when snowfall rates > 1inch/hour
2. At what wind speeds does drifting develop?
15-20 mph
3. What are inverted storms?
Dense snow on top of light, unconsolidated snow, resulting in instability. Often these are associated with warm fronts.
4. The danger from natural triggered (direct-action) avalanches from warm snowstorms is usually of short duration. True or False.
True. Settlement occurs more quickly at warm temperatures. Also, warm snowpack adjusts to load as it further compresses. It begins during or immediately after the storm, stabilizing the slope.
5. What two factors are most important for predicting avalanche potential?
Wind speed and direction
Precipitation intensity over time
6. Name the 10 contributory factors to direct action avalanches.
Old Snow Surface
New Snow Depth
New Snow Type
Old Snow Depth
Density (Total Water Content)
Snowfall Intensity
Precipitation Intensity
Wind Direction and Speed
Temperature
Settlement of New Snow
7. The general notion that south facing slopes are more stable in midwinter an north facing slopes in spring is based, at least in part, on consideration of
a) Depth hoar formation
b) Terrain pattern
c) Solar radiation
d) Geothermal heat
c.
8. Mountains can affect winds, making direction and speed unpredictable. True or False.
True. While it’s good to know the general wind direction and speed, be aware that topography can funnel winds, changing their direction and speed.
9. Surface hoar
a) Forms at night (or low sun angles) under clear skies
b) Is a deposition of water molecules form the air to the snow surface and solid objects
c) Becomes a weak layer when buried in the snowpack
d) All of the above.
d.
10. The significance of rain falling on the snowpack is that it
a) Results in a cold snowpack
b) Adds weight without adding strength
c) Erodes much of the snow cover
d) Produces small, well-bonded grains
b.
