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 'whumpfing' sound while traveling on snow typically indicate?
Answer: Sudden collapse of a weak layer, signaling high avalanche danger
Whumpfing is the sound of a weak layer collapsing under load, which is a critical red flag indicating the snowpack is primed for avalanche release.
Which crystal type forms through temperature gradient metamorphism in a strong temperature gradient (>10°C/m)?
Answer: Faceted crystals
Strong temperature gradients cause water vapor to migrate upward and recrystallize into faceted, angular grains that bond poorly and create weak layers.
A column of fresh snow is placed on a slope and immediately collapses. This most likely indicates:
Answer: A reactive weak layer capable of propagating a fracture
Sudden collapse during an Extended Column Test (ECT) or similar test indicates a fracture-prone weak layer that can propagate — a significant avalanche concern.
Which weather pattern most rapidly destabilizes a snowpack?
Answer: Rapid warming with rain at elevation
Rain on snow adds liquid water into the snowpack, rapidly lubricating weak layers and dramatically increasing wet avalanche hazard.
What is 'solar radiation loading' in avalanche forecasting?
Answer: Warming of south- and west-facing slopes by the sun, weakening surface snow strength
Solar radiation heats exposed slope aspects, melting surface bonds and triggering wet or loose avalanches, especially on south- and west-facing slopes in spring.
During an Extended Column Test (ECT), what does 'ECTP15' mean?
Answer: Fracture propagated across the column on tap 15 in the wrist zone
ECTP indicates a propagating fracture (P) during the Extended Column Test, and the number (15) is the tap count when fracture occurred, with wrist-zone taps being a moderate signal.
Which factor makes a buried weak layer MORE likely to persist and remain reactive over time?
Answer: Cold, dry weather with little new snow allowing continued faceting
Cold, dry conditions maintain the temperature gradient that drives faceting, keeping buried weak layers angular and poorly bonded for weeks or months.