disaster life_threatening ai_generated true

AI advises running downslope away from a volcanic eruption to escape pyroclastic flow (pyroclastic flow speed and channeling risk)

ID: disaster/volcano-eruption-run-downslope-myth

Also available as: JSON · Markdown · 中文
75%Fix Rate
86%Confidence
1Evidence
2024-05-18First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
USGS VHP (2024) active — — —
IAVCEI Guidelines (2023) active — — —

Root Cause

Pyroclastic flows travel at speeds up to 700 km/h down valleys and slopes, far faster than any human can run; running downslope puts the person directly in the flow's path and increases the chance of being overtaken.

generic

中文

火山碎屑流沿山谷和斜坡以高达700公里/小时的速度移动，远快于人类奔跑速度；向下坡逃跑会使人直接处于碎屑流的路径上，增加被追上的几率。

Official Documentation

https://www.usgs.gov/programs/VHP/volcanic-hazards

Workarounds

  1. 85% success Evacuate the danger zone immediately when an eruption warning is issued. Follow official evacuation routes that move perpendicular to the expected flow direction, not downslope. 
    Evacuate the danger zone immediately when an eruption warning is issued. Follow official evacuation routes that move perpendicular to the expected flow direction, not downslope.
  2. 40% success If caught in a pyroclastic flow, seek shelter in a sturdy building on the upper floors, away from windows and doors. Do not attempt to outrun it. 
    If caught in a pyroclastic flow, seek shelter in a sturdy building on the upper floors, away from windows and doors. Do not attempt to outrun it.
  3. 60% success Use a vehicle to drive away quickly, but only if traffic is clear and the route is perpendicular to the flow path. Do not drive into valleys or low areas. 
    Use a vehicle to drive away quickly, but only if traffic is clear and the route is perpendicular to the flow path. Do not drive into valleys or low areas.

中文步骤

  1. 在火山喷发警报发出时立即撤离危险区域。遵循官方疏散路线，这些路线垂直于预期的流动方向，而不是下坡方向。
  2. 如果被火山碎屑流困住，在坚固建筑的上层寻找庇护，远离窗户和门。不要试图跑赢它。
  3. 如果交通畅通且路线垂直于流动路径，可以使用车辆快速离开。不要驶入山谷或低洼地区。

Dead Ends

Common approaches that don't work:

  1. Running downhill as fast as possible to get away from the lava flow 90% fail

    Lava flows are slow, but pyroclastic flows are not; the person runs into the path of the pyroclastic flow, which is channeled by valleys

  2. Running perpendicular to the flow direction on the slope 80% fail

    Pyroclastic flows spread laterally and can surge over ridges; perpendicular escape may not be fast enough

  3. Hiding behind a large rock or tree downhill 95% fail

    Pyroclastic flows are hundreds of degrees Celsius and carry boulders; any obstacle is incinerated or swept away