Snowpack Analysis & Weather Interpretation Flashcards
7 cards from real ASC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Snowpack Analysis & Weather Interpretation flashcards as text
What does a wide, flat fracture line with a sharp, cohesive slab indicate about the avalanche that occurred?
Answer: A slab avalanche that released on a buried weak layer
A wide, clean crown with a cohesive slab below is the hallmark of a slab avalanche, where an entire layer released simultaneously along a weak layer.
In the North American Avalanche Danger Scale, which danger level accounts for the majority of avalanche fatalities?
Answer: Moderate (2) and Considerable (3)
Statistics consistently show that Considerable (3) and Moderate (2) danger levels account for the most fatalities because people underestimate the risk and travel in backcountry terrain.
What is 'aspect' in avalanche terrain analysis?
Answer: The compass direction a slope faces
Aspect describes which direction a slope faces (N, NE, E, etc.) and is critical because it determines sun exposure, wind loading patterns, and temperature effects on snowpack.
Which wind speed threshold is generally considered significant for wind slab formation?
Answer: 15–25 mph (24–40 km/h)
Winds of 15–25 mph and above can transport snow and deposit wind slabs on lee slopes and terrain features, creating one of the most common avalanche triggers.
A 'roller ball' or 'pinwheel' on a slope surface is a sign of:
Answer: Wet, loose surface snow losing cohesion, indicating wet avalanche potential
Rollers and pinwheels form when wet surface snow loses strength and rolls downhill, indicating the surface layer is saturated and wet slides are likely.
What is the primary purpose of digging a snow pit?
Answer: To examine snowpack layering, identify weak layers, and assess stability
Snow pits expose the stratigraphy of the snowpack, allowing identification of weak layers, crusts, and their relative positions, which informs stability assessment.
In avalanche forecasting, 'loading rate' refers to:
Answer: The rate at which new snow, rain, or wind-deposited snow adds stress to the snowpack
Loading rate describes how quickly mass is added to the snowpack; rapid loading (heavy snowfall, wind deposition, rain) overwhelms the snowpack's ability to adjust and increases instability.