The Victorian government in Australia has introduced new interim regulations for bunkers in which residents can take refuge when threatened by a bushfire. In order to install a fire bunker, a building permit must be obtained and the bunker must comply with performance requirements such as accessing and exiting the shelter, as well as utilities and the air supply. Residents need to purchase a bushfire bunker or shelter which is accredited, or satisfy a building surveyor that it meets the requirements contained in the regulations.
Under the new interim regulations, the first fire bunker has been accredited by the Victorian government. It is built by the Melbourne-based company Wildfire Safety Bunkers and is designed to be installed underground to shelter up to six people. The company emphasizes that the bunker should be used as a “last resort” and evacuation should be considered first.
The interim regulations will be in effect until proposed new national regulations are approved later in the year.
Research scientist Lachlan McCaw led a team that studied the effects that previous planned or unplanned fires had on the spread of the disastrous Black Saturday fires a year ago in Australia. Unsurprisingly, he concluded that the intensity was reduced and the areas provided anchor points for firefighters, but larger prescribed fires were more effective than small ones.
DUH. To many of us this is intuitive, but documenting this data can help to rebut the uninformed rants of those in Australia that are opposed to prescribed fires.
Dr McCaw said that across the areas burned on Black Saturday, there was no evidence that small-area fuel reduction had curbed the fires, but strong evidence of an impact where planned or unplanned burns had occurred within four years and over broad areas of more than 600ha.
Where the Kilmore fire, burning with great intensity about 3pm on Black Saturday, met a relatively small area of four-year-old growth, it was quickly outflanked.
About 6.30pm, when the fire met a 1600ha area burnt by wildfire in January 2006, it burned with low intensity.
Dr McCaw said the severity of the Beechworth fire on Black Saturday was reduced by burns that had been conducted one year, two years and four years previously, that had also provided “anchor points” for fire fighting.
Asked about the effectiveness of small “mosaic” burns that left areas of unburnt vegetation for biodiversity conservation, Dr McCaw said if the primary objective of planned burning was community protection, “you would have to be pursuing fairly high levels of fuel reduction”.
Two teenage boys were arrested for starting a fire in Australia on Black Saturday last February 7 in which a disabled resident burned to death. The Maiden Gully fire near Bendigo killed Kevin “Mick Kane, 48, destroyed 60 homes, caused $29 million in damages, and burned 875 acres.
The two boys, aged 14 and 15, are said to have started the fire, then were seen by witnesses when they returned to watch it. Later they were stopped by a police roadblock.
Between January 29 and March 26 they made 55 calls on a mobile phone to an emergency number, threatening operators and harassing them with obscene comments. Police used listening devices to investigate the pair.
The boys were each charged with arson causing death, deliberately lighting a bushfire, lighting a fire on a total fire ban day, and lighting a fire in a country area during extreme weather conditions. They face a total of more than 150 charges.
Brendan Sokaluk, 39, appeared on Tuesday in Melbourne Magistrates’ Court in Australia via video link from prison. He is facing 191 charges related to one of the fires that burned across Victoria on February 7, including 10 counts of arson causing death, intentionally causing a bushfire, criminal damage, recklessly causing injury, and possessing child pornography.
The Magistrate set a pretrial hearing date for May 31, where 610 witnesses are expected to testify over six weeks. The hearing will determine if there is enough evidence to begin a jury trial.
Numerous fires burned in Victoria on February 7, Black Saturday, killing 173 people and destroying more than 2,000 homes. Mr. Sokaluk is charged with setting one of the fires which killed 10 people.
The royal commission that is investigating the Black Saturday fires of February 7 in Australia was told by wildfire behavior expert Dr. Kevin Tolhurst that spot fires occurred a record 35 kilometers (21 miles) ahead of the main fire. Dr. Tolhurst also had some other interesting observations about fire behavior during the fires. Two examples are spot fires occurring off the flanks of a fire, and researchers studying fire behavior of small fires and extrapolating that to assume fire behavior on large fires would be similar. The latter was an issue during the 1988 Yellowstone fires when crown fire behavior did not match the existing prediction models.
Here is an excerpt from The Australian:
Dr Tolhurst said researchers had developed “warped ideas” about bushfire behaviour because they had studied comparatively small fires. This had flowed through to training of fire fighters and advice given to the public.
Dr Tolhurst, who has studied extended video of the February 7 fires, said most people expected a fire front that was like a “wave of fire”, which would pass in a matter of minutes. But during the Black Saturday disaster fire activity had lasted for hours in some cases, with up to an hour when radiated heat remained a danger.
“There’s no one front of fire,” Dr Tolhurst said. “It’s not a continuous wave of fire going through.”
The strong wind change caused by the arrival of a cold front late in the afternoon of Black Saturday created a “horror situation”.
“That’s the worst situation you can have,” Dr Tolhurst said.
Although cold fronts can bring cooler conditions, bushfires burn just as intensely for a number of hours after their arrival. The change in wind direction to a southerly or south-westerly will “blow out” the eastern flank of any fire burning at the time, pushing it in a new direction on a much wider front.
The size of the new fire front and the speed it travels will “catch people out”, Dr Tolhurst said.
He said 80 per cent of the damaged caused by bushfires in Victoria occurred after the arrival of a cold front and change in wind direction. Dr Tolhurst said the Black Saturday fires produced huge convection columns and pillars of smoke that made them burn more intensely.
The convection columns caused air to be sucked into the fires at ground level, creating localised cyclonic winds of up to 120kph and snapping trees off three or four metres above the ground. Higher winds created by fires could carry smoke and embers in a direction different from the prevailing wind that was driving the main fire front. This meant spot fires could occur not just ahead of the main front, but off the fire’s flank. On Black Saturday spot fires occurred up to a record 35 kilometres (21 miles) ahead of the main fire, Dr Tolhurst said.
It also made it difficult attempt to judge whether a fire was coming towards you by looking at the direction the smoke was blowing. Someone in the path of the fire could be “in the clear” in terms of seeing smoke.