WILDFIRE: LATEST LEARNINGS- v01.6

WILDFIRE: LATEST LEARNINGS

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General learning outcome:

SPECIFIC FIRE BEHAVIOUR:

Specific learning outcome:

Vorticity-driven Lateral Spread is a major factor in rugged landscapes.

Topic:

The potential consequences of Vorticity-driven Lateral Spread.

Expert Awareness for Advanced Firefighters & Fire Behaviour Analysts


Should a Vorticity-driven Lateral Spread event be initiated, the subsequent fire evolution will involve:
  • Intense spotting downwind of the flank of the event, for up to 6km, with all spots attaining headfire intensities and rates of spread and rapidly merging.
  • A vortex of dense smoke within the lee-slope eddy, with a major, dense, orange-coloured plume emerging from the flank. This is diagnostic.
  • The flank of that vortex expanding, laterally with respect to the prevailling wind, at up to 6 km/hr. Note that this takes the spotting zone, above, with it, resulting in fire spreading in two directions at once.
A major expansion of the flaming zone results – it may be some kilometres wide. This creates a convection column that maintains its thermal expansion (and thus prevents mixing with the surrounding air) up to the lifting condensation level. Should this occur, then a violent pyro-convection event will ensue.
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This website is dedicated to bringing forward the latest research findings. They are provided to allow firefighters to be made aware of critical safety issues ahead of the material being included in the national training curriculum.
Material prepared by Rick McRae for AFAC Research Dissemination Pilot Study, March 2012.