1. Most slab avalanches start between what angles?
30-45 degrees
2. What is the most dangerous slope shape
a) Convex
b) Concave
c) Straight
a.
3. Convexities increase _________ stress at the break in slope.
a) Compressive
b) Tensile
c) Shear
b.
4. List 6 indicators of an avalanche path
a. Area is devoid of trees on a heavily forested slope. This is indicative of avalanche activity
b. The trees are flagged, or the limbs are removed on the uphill side.
c. Trees are generally smaller and younger in a slide path
d. An abrupt change is species may indicate a slide path. Alder, vine maple, or aspen may colonize a path after a large avalanche before larger species take over.
e. Heavy debris (down trees, rocks etc) exposed in the spring or summer can mean the slope is an avalanche track
f. Avalanche debris
Other indicators/factors:
g. A long uniform gradient is more dangerous than a terraced one because it allows the avalanche to build up speed and energy. On a terraced slope, the slide slows down and spreads out when it hits the base of the terrace.
h. Cornices forming on a ridge line often form above avalanche paths
i. Slope aspect is an important factor in recognizing possible avalanche paths. Slopes that are to the lee of the prevailing winds can load up by wind deposition and slide. South facing slopes receive more direct sunlight and are more prone to wet slide activity in warmer weather. North facing slopes often can be dangerous because the sun never gets a chance to shine on them. This can lead to lower temperatures on theses slopes and extension of avalanche hazards there.
5. Name 5 key elements of a slope to be considered when evaluating avalanche potential
a. Angle
b. Elevation
c. Aspect
d. Surface
e. Shape/Configuration
6. Name 4 questions to consider when evaluating the consequences of a slide.
a. Are there trees or cliffs the slide would drag you through/over?
b. Where will the debris end up? Is there a terrain trap below that would funnel the debris?
c. How big will a slide be? Is it likely to be smaller soft slab that will break off at my feet or a larger hard slab that will break off up hill of my position?
d. How far down hill will a slide run before coming to a stop?
7. Cornices face towards ___________ slopes.
Leeward
8. A 10 degree slope is always safe. True or False?
a. False, it depends on what terrain is above and below this slope. Large avalanches can run way out onto the valley floor.
9. In order to trigger an avalanche, one must be on a dangerous slope. True or False?
False. One can remotely trigger an avalanche on a dangerous slope from adjacent flats or a ridge top in considerable, high or extreme avalanche danger.
10. Rank in order from safest (1) to most dangerous (4).
___ At home watching latest ski/board/sled video
___ Mid slope on 37 degree hill
___ On ridge above 37 degree hill
___ In v-shaped valley in unstable conditions
1.
3.
2.
4.
Unless you have really good avalanche skills, I’d recommend staying home when the avalanche advisory is above considerable. Try to travel on the windward side of ridges (above the danger) well back from cornices. Avoid terrain traps such as narrow drainages or gullies at all costs. In general, avalanche hazard is lower at lower elevations below the tree line than at higher elevations.
