Avalanche Formation & Terrain Recognition 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 Avalanche Formation & Terrain Recognition flashcards as text
Which snow crystal type is most commonly associated with the formation of weak layers that lead to slab avalanches?
Answer: Faceted crystals and depth hoar
Faceted crystals and depth hoar form under strong temperature gradients, creating weak, sugary layers that fail easily under stress.
What is the term for the temperature-driven metamorphism that converts snow into weak, angular crystals prone to avalanche formation?
Answer: Kinetic growth metamorphism
Kinetic growth metamorphism occurs when steep temperature gradients (>10°C/m) cause vapor to migrate and recrystallize into facets and depth hoar.
A convex roll on a mountainside is considered a high-hazard terrain feature primarily because:
Answer: It creates a tension zone where slabs are most likely to fracture
Convex rolls place the snowpack under tension, making them prime initiation zones where slab fractures commonly begin.
During which phase of a storm cycle is avalanche danger typically at its highest?
Answer: During and immediately after heavy snowfall
Loading rates during and right after heavy snowfall exceed the snowpack's ability to adjust, dramatically increasing instability.
What is a 'solar aspect' and why does it matter for avalanche terrain assessment?
Answer: The compass direction a slope faces relative to the sun's path
Solar aspect determines how much direct sun a slope receives, affecting snow temperature, melt-freeze cycles, and the location of persistent weak layers.
Which terrain trap significantly increases avalanche consequences even for small slides?
Answer: Cliff bands, creek beds, and gullies below the path
Terrain traps concentrate debris and burial depth; a small avalanche funneling into a cliff or creek bed can be fatal even when the slide itself is modest.
A lee slope in avalanche terrain refers to a slope that:
Answer: Is sheltered from the wind and accumulates wind-deposited snow
Lee slopes are sheltered from prevailing winds and collect wind-transported snow, creating slabs that can be much denser and thicker than windward slopes.