AVALANCHE-SLOPE-ANGLE-ERR safety physical_safety ai_generated true

AI tells a backcountry skier that a slope under 30 degrees is safe from avalanches on a High (Level 4) danger day, or that all south-facing slopes are safe in spring

ID: safety/avalanche-slope-angle-error

Also available as: JSON · Markdown · 中文
80%Fix Rate
88%Confidence
1Evidence
2025-02-14First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
North American Avalanche Danger Scale 2024 active — — —
CAIC Avalanche Forecast v3.2 active — — —
Avalanche.org 2025 active — — —

Root Cause

Avalanche danger depends on snowpack structure, not just slope angle; slopes under 30° can slide if triggered from above, and aspect (direction) interacts with sun exposure, wind loading, and temperature cycles; High (Level 4) means widespread instability on many aspects and elevations.

generic

中文

雪崩危险取决于雪层结构，而不仅仅是坡度；低于30°的坡度若从上方触发可能滑动，坡向（方向）与日照、风载和温度循环相互作用；高级（4级）意味着多个坡向和海拔广泛不稳定。

Official Documentation

https://avalanche.org/avalanche-danger-scale

Workarounds

  1. 90% success On High (Level 4) days, avoid all avalanche terrain (slopes over 30°) and terrain traps; travel only on low-angle (<20°) slopes with no overhead hazard; use 30-45-90 rule: avoid slopes 30-45°, be cautious of slopes >45° for cornice fall. 
    On High (Level 4) days, avoid all avalanche terrain (slopes over 30°) and terrain traps; travel only on low-angle (<20°) slopes with no overhead hazard; use 30-45-90 rule: avoid slopes 30-45°, be cautious of slopes >45° for cornice fall.
  2. 85% success Perform a terrain assessment: check slope angle with inclinometer, look for recent avalanche activity, avoid convex rolls and wind-loaded features; dig a snowpit and perform stability tests (ECT, CT) before committing. 
    Perform a terrain assessment: check slope angle with inclinometer, look for recent avalanche activity, avoid convex rolls and wind-loaded features; dig a snowpit and perform stability tests (ECT, CT) before committing.
  3. 80% success Use the 'Avaluator' or 'Slope Angle' app to map terrain; carry avalanche safety equipment (beacon, probe, shovel) and travel one at a time on suspect slopes. 
    Use the 'Avaluator' or 'Slope Angle' app to map terrain; carry avalanche safety equipment (beacon, probe, shovel) and travel one at a time on suspect slopes.

中文步骤

  1. 在高级（4级）危险日，避开所有雪崩地形（坡度超过30°）和地形陷阱；仅在低角度（<20°）且无上方危险的坡面行进；使用30-45-90规则：避开30-45°坡度，对>45°坡度警惕落雪檐。
  2. 进行地形评估：使用坡度计检查坡度角，观察近期雪崩活动，避开凸起和风载特征；挖雪坑并进行稳定性测试（ECT、CT）后再行进。
  3. 使用'Avaluator'或'Slope Angle'应用绘制地形；携带雪崩安全装备（信标、探杆、雪铲），在可疑坡面逐一通过。

Dead Ends

Common approaches that don't work:

  1. 70% fail

    Trigger from above (skier, cornice fall) can release slab on low-angle terrain below; terrain traps increase risk.

  2. 65% fail

    Solar warming melts snowpack, creating wet slabs that can release; south aspects are most prone to wet avalanches in spring.

  3. 75% fail

    Micro-terrain features (ridgelines, gullies) can create localized instability even in areas rated 'Moderate'.