Terrain Selection Guide
Understanding terrain features and how to choose safe travel routes. Terrain selection is your most powerful risk management tool.
Slope Angle
The single most important terrain factor
Critical Angles to Know
Safe from Slab Avalanches
Generally too flat for slab avalanches to form or run. Safe terrain for avalanche conditions.
Low Risk Zone
Avalanches can occur but are less common. Good margin of safety for most conditions.
Sweet Spot (and Danger Zone)
Ideal skiing angle but also where most slab avalanches occur. Requires careful assessment.
Extreme Terrain
Very steep. Snow may sluff naturally before building dangerous slabs. Expert terrain only.
Measuring Slope Angle
Use an inclinometer (app or physical device) to measure slope angles. Most smartphones have built-in inclinometer apps. Measure the steepest part of the slope you plan to descend.
Aspect (Direction Slope Faces)
Determines sun and wind exposure
The direction a slope faces affects how much sun and wind it receives, which directly impacts avalanche danger.
North Aspects
- •Less sun exposure (cold, preserve weak layers longer)
- •Slower to stabilize after storms
- •Best powder but persistent problems
South Aspects
- •Maximum sun exposure (warming)
- •Stabilizes faster but wet avalanche risk
- •Afternoon timing critical in spring
East/West Aspects
- •Morning sun (east) or afternoon sun (west)
- •Moderate solar radiation
- •Often wind-loaded (prevailing winds)
Check the Forecast
Avalanche forecasts specify which aspects are problematic. Always check before heading out.
Terrain Traps
Features that increase consequences
Terrain traps are features that can multiply the severity of even a small avalanche by concentrating debris or creating obstacles.
Gullies & Couloirs
Narrow, confined spaces where snow piles deep. A small slide can bury you completely. Very high consequence terrain.
Trees & Rocks
Impact hazards that can cause trauma injury even in small slides. Debris piles against obstacles creating deep burials.
Cliffs & Bergschrunds
Being carried over a cliff or into a crevasse dramatically increases injury and burial risk.
Flat Areas Below Slopes
Benches, roads, or flat runouts where debris piles deep and doesn't spread out.
Safe Zones & Islands of Safety
Where to regroup and make decisions
Dense Timber
Trees spaced closely enough that you can't ski through them easily. Anchors the snowpack and protects from avalanches above.
Ridgetops
Above avalanche starting zones. Safe from slides but may be wind-exposed. Good for observations.
Low-Angle Benches
Flat or low-angle terrain between slopes. Good regrouping spots if not in a runout zone.
Below Avalanche Runout
Far enough down-valley that debris won't reach you. Know typical avalanche runout distances.
Practical Terrain Selection
Start Conservative
Begin trips in low-consequence terrain. If conditions seem stable and you find no red flags, you can gradually move to more committing terrain.
Key Strategies
- •Match terrain to conditions: Higher avalanche danger = simpler terrain choices
- •Have a Plan B and C: Alternative routes if conditions aren't as expected
- •One slope at a time: Assess each feature individually before committing
- •Manage exposure: Minimize time in avalanche terrain, use safe zones
- •Escape routes: Always know where you'll go if conditions deteriorate