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
Which snowpack test result indicates the HIGHEST concern for avalanche propagation potential?
Answer: ECTP12 with sudden planar fracture and 'shooting cracks'
ECTP on a low tap count with sudden collapse and shooting cracks indicates both easy initiation and high propagation potential — the most dangerous combination.
What does 'spatial variability' mean in snowpack analysis?
Answer: The fact that snowpack conditions can differ significantly over short distances across a terrain
Spatial variability means a stable test result in one location does not guarantee stability across an entire slope, because wind, terrain, and aspect create highly variable conditions.
What happens to a melt-freeze crust when it becomes buried under new snow?
Answer: It can become a sliding surface for slab avalanches, especially if weak layers form above it
Buried crusts are hard and slippery, providing a low-friction interface that can act as a sliding surface when a slab forms above a weak layer sitting on or near the crust.
What is a 'convex roll' and why is it an avalanche concern?
Answer: A slope feature where the angle increases sharply, creating tension fractures in the snowpack
Convex rolls put the snowpack in tension at the roll-over point, making it more susceptible to fracture initiation, especially when a buried weak layer is present.
How does a temperature inversion affect snowpack stability?
Answer: It warms upper elevations while keeping lower slopes cold, potentially destabilizing high-elevation snowpack faster
During a temperature inversion, warm air sits above cold air, meaning high-elevation slopes may warm and lose stability while lower slopes remain frozen and stable.
What is the significance of 'recent avalanche activity' as an avalanche observation?
Answer: It is one of the most reliable red flags indicating the snowpack is actively unstable
Natural or human-triggered avalanche activity confirms that the snowpack has failed recently, indicating active instability that is likely widespread across similar terrain.
Which layer in the snowpack is called a 'bed surface'?
Answer: The layer below a weak layer on which a slab slides after release
The bed surface is the layer immediately below the weak layer; after a weak layer fractures, the slab slides on the bed surface, which is often a harder or denser layer.