ASC Snowpack Analysis & Weather Interpretation 1 — Questions and Answers
Question 1: Why is snowpack layering important in avalanche forecasting?
- They help locate water sources
- They make trails easier to mark
- They indicate snow color
- They determine snow stability (Correct answer)
Correct answer: They determine snow stability
Snowpack layering is critical in avalanche forecasting because it reveals the structure and stability of the snowpack. Different layers, such as weak faceted snow, strong wind slabs, or ice crusts, interact with each other, and understanding these interfaces helps predict where and when a collapse might occur.
Question 2: Which weather condition contributes most to rapid snowpack changes?
- Light snow
- Sunshine and warming (Correct answer)
- Overcast skies
- Wind chill
Correct answer: Sunshine and warming
Sunshine and warming temperatures are major contributors to rapid snowpack changes, especially in spring or during warm spells. They can quickly destabilize the snowpack by causing surface melting, creating wet snow avalanches, or weakening bonds between layers, increasing the risk of slides.
Question 3: What does a 'whumpfing' sound indicate?
- A distant thunderstorm
- Ice cracking
- Snow compaction
- Weak layer collapse (Correct answer)
Correct answer: Weak layer collapse
A 'whumpfing' sound is a distinct audible sign that a weak layer within the snowpack has collapsed under the weight of a person or new snow. This indicates significant instability and is a strong warning sign that an avalanche could be triggered.
Question 4: How does wind influence snow distribution?
- Reduces snowpack depth
- Increases air pressure
- Forms cornices and slabs (Correct answer)
- Melts surface snow
Correct answer: Forms cornices and slabs
Wind significantly influences snow distribution by picking up and transporting snow particles. This process leads to the formation of cornices, which are overhanging masses of snow on ridges, and dense wind slabs on leeward slopes, both of which are common triggers or components of avalanches.
Question 5: What tool is used to examine snow layers?
- Ice axe
- Thermometer
- Snow saw
- Snow pit (Correct answer)
Correct answer: Snow pit
A snow pit is a crucial tool for examining snow layers and assessing snowpack stability. By digging a pit, avalanche professionals and recreationalists can visually inspect the different layers, identify weak layers, and perform stability tests to understand the snowpack's current condition.
Question 6: Which type of snow is most prone to sliding?
- Corn snow
- Wet snow
- Faceted snow (Correct answer)
- Fresh powder
Correct answer: Faceted snow
Faceted snow crystals are angular, cup-shaped grains that form in cold, dry conditions with a strong temperature gradient within the snowpack. These crystals bond poorly with each other and with surrounding layers, creating persistent weak layers that are highly prone to collapse and sliding.
Question 7: Which instrument helps track wind speed affecting snow transport?
- Barometer
- Anemometer (Correct answer)
- Hygrometer
- Snow gauge
Correct answer: Anemometer
An anemometer is an instrument specifically designed to measure wind speed. Monitoring wind speed is vital in avalanche forecasting because wind is a primary factor in snow transport and the formation of dangerous wind slabs and cornices, which are major avalanche hazards.
Question 8: What role does solar radiation play in snowpack stability?
- Creates rain clouds
- Thickens snowpack
- Stabilizes the snow base
- Alters snow layers with melt and refreeze (Correct answer)
Correct answer: Alters snow layers with melt and refreeze
Solar radiation, especially direct sunlight, significantly impacts snowpack stability by causing surface melting and subsequent refreezing. This process can create ice crusts, weaken bonds between layers, or lead to the formation of wet snow, all of which can destabilize the snowpack and increase avalanche risk.
Question 9: How can weather forecasts assist avalanche prediction?
- Predict animal movement
- Plan events
- Monitor temperature only
- Anticipate snowpack changes (Correct answer)
Correct answer: Anticipate snowpack changes
Weather forecasts are essential for avalanche prediction because they allow forecasters and backcountry users to anticipate how upcoming weather will affect the snowpack. Information on new snowfall, temperature changes, wind, and precipitation helps predict snowpack loading, weakening, or stabilization, guiding safer travel decisions.
ASC Snowpack Analysis & Weather Interpretation 1
Why is snowpack layering important in avalanche forecasting?