AVALANCHE-ANGLE-ERR safety physical_safety ai_generated partial

AI tells a backcountry skier that a slope under 30 degrees is safe from avalanches on a High (Level 4) danger day, or that they can ski one at a time without risk

ID: safety/avalanche-slope-degree

Also available as: JSON · Markdown · 中文
77%Fix Rate
86%Confidence
1Evidence
2024-02-28First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
danger_scale active — — —
terrain_classification active — — —

Root Cause

Avalanche danger ratings are not solely slope-angle dependent; factors include snowpack instability, wind loading, terrain traps, and trigger points. Even slopes under 30 degrees can avalanche if wind-loaded or if the snowpack is weak; skiing one at a time does not eliminate risk if the slope is connected to a trigger zone above.

generic

中文

雪崩危险等级不仅取决于坡度；因素包括雪层不稳定性、风载、地形陷阱和触发点。即使是30度以下的斜坡，如果有风载或雪层薄弱也可能发生雪崩；逐个滑雪并不能消除风险，如果斜坡上方有触发区。

Official Documentation

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

Workarounds

  1. 85% success Use the Avalanche Terrain Exposure Scale (ATES) to classify terrain, and check the local avalanche forecast (e.g., https://avalanche.org). On High danger days, avoid all avalanche terrain (slopes >25 degrees with wind loading or weak snowpack). 
    Use the Avalanche Terrain Exposure Scale (ATES) to classify terrain, and check the local avalanche forecast (e.g., https://avalanche.org). On High danger days, avoid all avalanche terrain (slopes >25 degrees with wind loading or weak snowpack).
  2. 75% success Perform a full snowpack test (e.g., compression test, extended column test) to assess stability before skiing any slope. Carry avalanche safety gear (transceiver, probe, shovel) and travel one at a time through safe zones only. 
    Perform a full snowpack test (e.g., compression test, extended column test) to assess stability before skiing any slope. Carry avalanche safety gear (transceiver, probe, shovel) and travel one at a time through safe zones only.

中文步骤

  1. Use the Avalanche Terrain Exposure Scale (ATES) to classify terrain, and check the local avalanche forecast (e.g., https://avalanche.org). On High danger days, avoid all avalanche terrain (slopes >25 degrees with wind loading or weak snowpack).
  2. Perform a full snowpack test (e.g., compression test, extended column test) to assess stability before skiing any slope. Carry avalanche safety gear (transceiver, probe, shovel) and travel one at a time through safe zones only.

Dead Ends

Common approaches that don't work:

  1. Check only slope angle with an inclinometer app 75% fail

    Angle alone is insufficient; must also assess snowpack, weather, and recent avalanche activity. Many avalanches occur on 30-35 degree slopes.

  2. Ski one at a time and have everyone else watch from the bottom 80% fail

    Watching from the bottom is dangerous; if an avalanche occurs, the observer may be caught. Safe zones are on ridges or above the start zone.

  3. Stay on slopes under 25 degrees to be completely safe 65% fail

    Even low-angle slopes can avalanche if wind-loaded or if the slope is connected to a steeper trigger zone above. Terrain traps (e.g., gullies) increase risk.