Originally Posted By: Susan
It is said that firestorms create their own wind, and even their own tornados.


Wildland fires can and do get large enough to create their own localized weather systems (as the Australian fires are certainly large enough to do). There can be enough heat to generate updrafts that can take a flaming pine cone aloft and carry it several kilometers downwind. Wildland firefighters during entrapments have said that the flame front sounded like an oncoming train - that's a lot of air movement.

"When the first fire front came across us, I would estimate that the winds were probably in excess of 70 miles per hour.The sense of power that you had around you, that energy release that we had around us was just absolutely incredible. It was a very humbling experience. I mean you felt very small and very insignificant at that point.
- Entrapment survivor

"Tornado" is a little misleading...think "firewhirl" which is like a dust devil, but with flame instead of dust. Firewhirls demonstrate atmospheric instability and the potential for extreme fire behavior but are typically small (maybe 10 meters high?), short lived (a few seconds) and their associated danger is their potential for blowing a control line.


Edited by yelp (02/11/09 04:32 PM)
_________________________
(posting this as someone that has unintentionally done a bunch of stupid stuff in the past and will again...)