'Never seen before': CQ stared down threat of a firestorm
IT WAS an event rarely seen in Queensland and was described at the time as "no different to a category five cyclone coming straight through your door".
Wednesday, November 28 was the day the CQ bushfire crisis arguably hit its peak and became a major cause for concern for residents, emergency services personnel and the state's politicians.
On that day Queensland Fire and Emergency Services manager of predictive services Andrew Sturgess fronted the media in Brisbane, flanked by QFES commissioner Katarina Carroll, Queensland Police Service deputy commissioner Bob Gee, Premier Annastacia Palaszczuk and Emergency Services Minister Craig Crawford.
Then the "f'' word was mentioned - firestorm.
"We're not talking about a very hot day or a very bad fire day - we are talking about records," Mr Sturgess said at the time.
"These are conditions we've never seen before. We'll see fire behaviour we've never seen before."
Mr Sturgess explained the type of unique atmospheric conditions that were making the Deepwater bushfires a potentially catastrophic concoction.
"Instability in storms is the atmosphere enhancing upward motion," he said.
"Burning materials lofted up into the atmosphere - there are very strong winds above the surface that will deposit that burning material well ahead of the fire and beyond containment lines potentially behind firefighters and potentially into communities."
Mr Crawford described the situation on November 28 as an "unprecedented" event.
"As an old Victorian firefighter I saw Ash Wednesday and I saw those big jobs down there and they are the kind of conditions that we're looking at today," he said at the time.
Mr Gee backed the minister's comments during the press conference.
"As the minister said, this is not normal for Queensland. People will burn to death and their normal approaches most probably won't work if this situation develops the way its predicted to develop.
"It's no different to a category 5 cyclone coming straight through your door."
Now almost three weeks after that event, Mr Sturgess has detailed the dynamics of a firestorm and what emergency services were up against.
"What I was trying to communicate there when I mentioned a firestorm is fire is largely driven by the surface conditions - the wind temperature, humidity and the amount of moisture in the air at the surface.
"But there was a whole lot of energy that was going to come from the atmosphere.
"The atmosphere is unstable which means the amount of stability either enhances vertical motion or suppresses vertical motion - when it's unstable it enhances vertical motion.
"This means more burning material gets lifted up, the smoke plume has a lot of in-draft so that increases the fire intensity, but that in-draft can get really strong and start lifting lots of burning material and with the strong winds above the surface they're not factored into the fire behaviour models, not factored into rates of spread or the fire danger rating because that's all about the surface."
Mr Sturgess told The Observer the danger was in what was happening in the atmosphere, not just on the ground.
"We typically think of a fire as spreading with a flaming front - there's a whole lot of embers being deposited ahead of fire.
"Firestorm means the fire is all around us... it's an area of fire and it's stormy because there's so much convection going on and such strong winds.
"The fire is in an area rather than a flaming front spreading across the landscape, it's all these embers getting dumped ahead of the fire and igniting new fires ahead of the fire.
"Then they interact with the main fire and that is the kind of firestorm conditions... lightning, thunder, and that's the kind of environment we were in on November 28."