With Victoria
now experiencing the summer bushfire season we are again being urged to leave our homes and businesses to the mercy of bushfire through this year's questionable “leave and live” message.
I commenced this blog to primarily to assist my clients and anyone else interested to improve their understanding of bushfire behaviour and related building and planning scheme requirements, particularly the Bushfire Management Overlay (BMO).
However, the broad scale urging of people to leave their homes and businesses unprotected when bushfire may threaten is dangerous policy in that it serves to unnecessarily frighten many people, who with some detailed site-specific coaching and personal capability assessment could stay with their homes to protect them from ember attack — it's now well-known that ember attack is the major cause of building loss in a bushfire.
While
there will be some people who should consider where they would be safer in the event
of bushfire threatening their home, particularly those “old stock” homes that
have no built-in bushfire protection measures and are close to forest or large
tracks of scrub, such a broad-brush message can only create uncertainty and
possibly expose homes that only need active defence against ember attack.
Such
active defence can be undertaken before and after the passage of a fire front
by well prepared occupants of the home. With fire brigade units unable to
protect every dwelling and concentrate on stopping the spread of a fire, survival of the dwelling may depend entirely on the
occupants defending it themselves.
One of my objectives with this blog is to provide some understanding of bushfire and how it spreads to involve buildings. As part of this coaching my Sunday, 15
June 2014 “Bushfire explained – Part 2: How bushfire move across the landscape” (click here) I provided information and before and after photographs of a house at Humevale lost in the 2009 bushfires.
I’ve
since found a few more photographs that confirm the loss of that undefended home
to ember attack, particularly at the vulnerable underfloor timber entrance door.
As in the earlier photographs, the clean and tidy lines of this brick veneer dwelling show the only direct bushfire threat to be in the form of nearby trees and shrubs. Significantly, the garage and contents at right remained unaffected by the passing fire.
The following photographs show scorched, but unburnt leaves on the adjacent trees and shrubs. I attribute the bare branches in the third photograph with the water pump and hot water service in the background to be the heat of the fire in the dwelling drying the moisture from the leaves sufficient to ignite them, but note not all the leaves.
The following photographs show scorched, but unburnt leaves on the adjacent trees and shrubs. I attribute the bare branches in the third photograph with the water pump and hot water service in the background to be the heat of the fire in the dwelling drying the moisture from the leaves sufficient to ignite them, but note not all the leaves.
The remains of an old timber dwelling — also shown in the background of one of the above photographs — completely unprepared to withstand ember attack is worth including as it shows that the fire driven by strong wind burning uphill did not extend to involve the eucalypt and pine tree foliage (crowning).
Bushfire Survival
Referring to the earlier statement: “With fire brigade units unable to protect every dwelling and concentrate on stopping the spread of a fire, survival of the dwelling may depend entirely on the occupants defending it themselves”.
The coastal town of Lorne is a good example of the potential for enormous, but avoidable property loss that includes numerous dwellings and a range of commercial properties, potentially millions of dollars.
According to this Community Information Guide (click here) Lorne has been assessed as being at “EXTREME” risk due to bushfire. It also includes the following statement “The Fire Danger Rating is CODE RED. Homes aren’t designed to withstand a bushfire during these conditions. Any fire that starts and takes hold will be so intense that you won’t be safe to stay and defend your home – no matter how well prepared it is”. This statement begs the question, including buildings well inside the perimeter of the township where the only real threat will be ember attack or a fire in a neighbouring garden that could be suppressed by well prepared residents?
If large numbers of people choose to not be in Lorne on a forecast Code Red or extreme bushfire threat day, will the fire agencies pre-position sufficient resources to protect the otherwise undefended properties? Resources that if not pre-positioned in the town may not be able to get there due to the areas of forest the three major roads to Lorne pass through?
There are contradictions in this community information guide that coupled with the hype the news media gives to bushfire events and community warnings can only serve to confuse or frighten the vast majority of people unfamiliar with bushfire behaviour.
Extend this to the numerous other towns and settlements in Victoria covered by similar community information guides and the potential is there for enormous property loss. Much of this property loss could be avoided if the government insisted on resources being committed to site-specific real fire behaviour education and mentoring of the large army of people within these at-risk communities — if necessary by diverting money from firefighting equipment and fire station building programs.
The “downstream” consequences of property loss seems to have been overlooked by the government, Marysville being one notable example. The loss of the family home or a business is just as injurious to the individuals involved and ultimately costly to the broader community. Preferable that the loss be avoided in the first place.
Unfortunately, the unhelpful broad-brush attitude of the government in dealing with development in areas subject to the Bushfire Management Overlay can be aligned to the no-risk “everybody out” approach.
The coastal town of Lorne is a good example of the potential for enormous, but avoidable property loss that includes numerous dwellings and a range of commercial properties, potentially millions of dollars.
According to this Community Information Guide (click here) Lorne has been assessed as being at “EXTREME” risk due to bushfire. It also includes the following statement “The Fire Danger Rating is CODE RED. Homes aren’t designed to withstand a bushfire during these conditions. Any fire that starts and takes hold will be so intense that you won’t be safe to stay and defend your home – no matter how well prepared it is”. This statement begs the question, including buildings well inside the perimeter of the township where the only real threat will be ember attack or a fire in a neighbouring garden that could be suppressed by well prepared residents?
If large numbers of people choose to not be in Lorne on a forecast Code Red or extreme bushfire threat day, will the fire agencies pre-position sufficient resources to protect the otherwise undefended properties? Resources that if not pre-positioned in the town may not be able to get there due to the areas of forest the three major roads to Lorne pass through?
There are contradictions in this community information guide that coupled with the hype the news media gives to bushfire events and community warnings can only serve to confuse or frighten the vast majority of people unfamiliar with bushfire behaviour.
Extend this to the numerous other towns and settlements in Victoria covered by similar community information guides and the potential is there for enormous property loss. Much of this property loss could be avoided if the government insisted on resources being committed to site-specific real fire behaviour education and mentoring of the large army of people within these at-risk communities — if necessary by diverting money from firefighting equipment and fire station building programs.
The “downstream” consequences of property loss seems to have been overlooked by the government, Marysville being one notable example. The loss of the family home or a business is just as injurious to the individuals involved and ultimately costly to the broader community. Preferable that the loss be avoided in the first place.
Unfortunately, the unhelpful broad-brush attitude of the government in dealing with development in areas subject to the Bushfire Management Overlay can be aligned to the no-risk “everybody out” approach.
This is the same for the communities of Tarwin Lower , Venus Bay and Walkerville , as the community " plan " the same document you refer to is of little use if it not backed up with community education , Fire Danger Meters on boundaries of TFB districts do little more than confuse travellers , the scare campaign seems to be the easy out , it is more difficult to actually educate what is happening on the ground ?
ReplyDeleteThe issue of warning people of the Fire Danger has become even more confusing with the introduction of. Electronic Fire Danger Boards , it seems that thes boards are not tagged as to the TFB District .
ReplyDeleteAt Pound Creek the Electronic Sign is in ( Central ) TFB area , travellers entering the Central Fire Ban District have a variety of sinage , the BassCoast Fire Danger Period sign , a Central Fire District Sign , the Electronic Fire Danger Clock , across the Creek in the other direction travellers are advised they are entering the West and South Gippsland Fire Ban District ,along with the Shire Fire Danger Sinage , no Fire Advisary Clock .
These invisible boundaries make it a nightmare as travellers move across the State .
The TFB Districts are very large and sinage on boundaries show the Fire Danger Rating for the highest level in that District as in the case of Pound Creek the conditions don't change across the boundary , difficult to educate people that it's a worst case descriptive !
The message boards advising people that they are entering a Very High Fire Danger Area offer little assistance other than they should listen to the ABC Radio or a local FM Station .
The message given via CFA of Leave And Leave Early is of little assistance as there is no other education or advice on these message boards as were to go ?
The lessons of Black Saturday are still to be learnt , as many of the 52 named townships have had little or no work done in the way of Fire Protection .
There have been very few Places of Last Resort established , no Refuges established , the easy option is to advise residents and travellers to Leave or don't go in the first place
It will take anothe tragedy to kick start the program again as it appears advise Of Leave and Leave Early will be the mantra for some time !
I agree John that more education for house occupants, planners and the community generally is needed. For a fire to burn there are 3 elements required, usually depicted as a triangle. These are fuel, oxygen and heat. If any one is removed a fire is extinguished. The one that can be removed most easily from around a house obviously fuel. Heat can also be shielded against in some circumstances. It needs to be understood that not all trees need to be removed. It is the 'available fuel' that burns in a fire front. That is defined as 6mm diameter and smaller. The larger sized branches, logs, etc. are ignited and burn out after the main front has passed. The burn out time, the time from when the fire front reaches a particular point on the ground to when the front has passed it is measured in seconds and will be up to around 150 to 180 seconds with a heavy fuel load. Tree canopies are ignited when there is enough fuel under them to heat them to ignition point. Rough barked eucalypts can assist ignition with fire traveling up the trunks but without enough heat from the fire underneath a crown fire will not be initiated or sustained. If tree crowns are separated and the fuel load beneath removed a house should be a safe refuge and if occupied at the time residents can, as you say John, prepare for the fire and go out when the front has passed and deal with embers, etc. In the Ash Wednesday fires there was a sliding scale of survival of houses according to the number of people present in the house at the time. If one person was present there was higher percentage of houses that survived than if no-one was present. If 2 people were present the percentage was higher again and so on until there were no houses lost when 4 or more people were inside. This was before there were any building controls for making houses fire resistant.
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