NSW fires expected to generate bizarre fire cloud

A BIZARRE fire cloud could form over two major fires ranging in NSW if weather conditions from Tuesday deteriorate as expected tomorrow.

Fairfax Media reports the unique weather phenomenon - also called a pyrocumulus - occurs when a large fire is coupled with an unstable atmosphere.

Rural Fire Service spokeswoman Natalie Sanders said the State Mine fire, which stretches across more than 42,000 hectares, had generated a pyrocumulus last Thursday and similar, unstable conditions were forecast for Wednesday.

''If these fires are still going strong, there's a potential for that to happen again,'' she said.

Andrew Sullivan, a leading bushfire behaviour researcher with the CSIRO, said the phenomenon required a fire generating a significant amount of heat.

As it burned, the hot air it released would rise as a column into the atmosphere. As air moved upwards, it was quickly replaced by cooler air, a process that produced a convection column.

Meanwhile, the NSW Rural Fire Service has revealed firefighters will deliberately link the major State Mine and Mount Victoria fires to help them manage the situation.

Strong winds picked up early this morning, hampering back-burning efforts, but firefighters will now take advantage of a lull, the ABC reported.

Firefighters will link the eastern edge of the two fires in a controlled way through back-burning efforts.

"That is principally focused on trying to stop those two fires coming together and joining with the fire down at Springwood and Winmalee," RFS commissioner Shane Fitzsimmons said at a briefing.

An emergency warning remains for the State Mine fire, while there are three watch-and-act alerts at Mount Victoria, Springwood and in the Southern Highlands.



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