ASC Risk Assessment & Mitigation 2 — Questions and Answers
Question 1: Which snowpack layer characteristic is most indicative of a persistent weak layer capable of triggering avalanches weeks after burial?
- High density and strong bonding
- Faceted crystals with poor interlayer bonding (Correct answer)
- Rounded grains with good settling
- Wind slab with uniform hardness
Correct answer: Faceted crystals with poor interlayer bonding
Faceted crystals form through temperature gradient metamorphism and maintain weak bonds even after burial, creating persistent weak layers.
Question 2: When evaluating avalanche risk on a slope, what does a 'whumpfing' sound from the snowpack indicate?
- Normal snow settling under foot pressure
- A buried weak layer collapsing under load (Correct answer)
- Wind crust fracturing near the surface
- Dense snow compacting during warming
Correct answer: A buried weak layer collapsing under load
Whumpfing indicates sudden collapse of a buried weak layer, a clear sign of an unstable snowpack with high avalanche potential.
Question 3: A group is planning a ski tour. Recent loading from 18 inches of new snow has occurred. What is the MOST appropriate risk mitigation strategy?
- Proceed normally since 18 inches is below the danger threshold
- Avoid convex rolls and lee slopes, travel one at a time on risky terrain (Correct answer)
- Only travel during midday when snow is warmest and most stable
- Increase group spacing to 100 yards on all terrain
Correct answer: Avoid convex rolls and lee slopes, travel one at a time on risky terrain
Avoiding terrain traps and convex rolls while practicing one-at-a-time travel limits exposure and reduces consequence if an avalanche releases.
Question 4: The 'Obvious Clues' category in avalanche risk assessment includes which of the following?
- Moderate winds in the last 24 hours
- Recent avalanche activity visible on surrounding slopes (Correct answer)
- A gradual rise in daytime temperatures
- New snow accumulation of less than 6 inches
Correct answer: Recent avalanche activity visible on surrounding slopes
Recent avalanche activity on surrounding slopes is one of the strongest obvious clues of current instability.
Question 5: What is the primary purpose of the Avalanche Terrain Exposure Scale (ATES)?
- To measure snowpack stability using a numerical index
- To classify route difficulty based on avalanche terrain complexity (Correct answer)
- To forecast daily danger ratings for backcountry zones
- To score individual rescuer competency in the field
Correct answer: To classify route difficulty based on avalanche terrain complexity
ATES classifies terrain into Simple, Challenging, and Complex categories based on avalanche exposure to help trip planners match terrain to skill and conditions.
Question 6: Which wind speed threshold is commonly cited as sufficient to transport snow and load lee slopes with wind slab?
- 5 mph (8 km/h)
- 15 mph (25 km/h) (Correct answer)
- 35 mph (56 km/h)
- 55 mph (88 km/h)
Correct answer: 15 mph (25 km/h)
Winds above roughly 15 mph can move snow and deposit wind slabs on lee aspects, creating avalanche-prone conditions.
Question 7: In the context of human factors in avalanche accidents, 'heuristic traps' refer to:
- Physical terrain features that funnel travelers into avalanche paths
- Mental shortcuts that lead to poor risk decisions in the field (Correct answer)
- Rescue equipment failures caused by operator error
- Incorrect interpretation of snowpack test results
Correct answer: Mental shortcuts that lead to poor risk decisions in the field
Heuristic traps are cognitive biases—such as familiarity, commitment, and social pressure—that cause experienced travelers to underestimate avalanche risk.
ASC Risk Assessment & Mitigation 2
Which snowpack layer characteristic is most indicative of a persistent weak layer capable of triggering avalanches weeks after burial?