WILDFIRE: LATEST LEARNINGS- v01.6

WILDFIRE: LATEST LEARNINGS

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General learning outcome:

SPECIFIC FIRE BEHAVIOUR:

Specific learning outcome:

Violent pyro-convection may involve a pyro-cumulonimbus, pyro-tornadogensis and ember storms.

Topic:

The phenomena associated with pyro-Cbs, including ember storms, lightning and tornadoes.

Operational Awareness for Advanced Firefighters & Fire Behaviour Analysts


A pyro-Cb may exhibit many of the features of a true thunderstorm:
  • Tornadoes.
  • Very large fire whirls.
  • Lightning.
  • Downburst fronts and squalls.
They may move at up to 65 km/hr, as determined by weather radar. Fire whirls are attached to the ground, but may leave the burnt area, carrying fire with them. Fire tornadoes are attached to the base of a pyro-Cb, and may lift-off from the ground repeatedly as they travel. They may be filled with fire and embers. They produce surface winds of over 250 km/hr, and have vertical air flow of over 150 km/hr. They are a major hazard to fire aviation. Lightning has, on a number of occasions, started new fires over 20km downwind. Downbursts can produce rapid changes in fire spread, endangering fire crews.
Pyro-Cbs may exceed 15 km in height and reach into the upper atmosphere.
Operations Officers need to carefully consider the implications of these features for the safety of crews and the public. There should be a Red Flag Warning (Plume-driven fire) in place.
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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.