Myths About Bushfires

A number of ideas have become entrenched in the popular mythology surrounding bushfires. Some of these can lead to people making poor decisions during fires and the fire danger period. Here are some of the 'myths' about bushfires and our perspective on these situations.

Myth
In major fires 'fireballs' are unstoppable and can move across open ground.
Reality
This is a rare event that can happen, but only under extreme weather conditions. Where there is incomplete combustion of fuels under extreme conditions, there can be pooling of unburnt gases which are too "rich" to burn. When there is mixing with air resulting in an appropriate ratio of unburnt gasses to air, any ignition will result in a short explosive burst of fire - a "fireball". http://eprints.ma.man.ac.uk/877/01/covered/MIMS_ep2007_139.pdf

Myth
In firestorms fire can travel quickly through the tree crowns without a ground fire.
Reality
Where there is heavy ground fuel, fires can move into the crowns of trees. If there is little ground fuel, or if there is no ground fire, crown fires will not be sustained for more than a very short distance.

Myth
Fires can travel at 'the speed of an express train' through the forest.
Reality 
The fastest rate-of-spread or "speed" of fires ever recorded is about 18 km/hr in grassland, and about 6 km/hr in forest. Spotting (new fires starting from burning material carried by wind) can cause rapid spread of fires, and spotting distances can be more than 10km, which can give the impression that fires are burning through an area more rapidly than they are actually burning past a stationary observer.

Myth
Houses "explode" in fires.
Reality
There are no substantiated examples of a house exploding in a bushfire. However, sometimes fires can smoulder in the ceiling, and if a hole burns to allow air to enter, dust and other debris in the ceiling can allow the house to suddenly burn very quickly. This can happen up to several hours after the embers enter the roof space. High winds often associated with extreme bushfires can also destroy houses during fires, allowing embers to enter, and result in very rapid ignition and house loss.

Myth
Sheltering in a cellar, dugout or bunker is the safest alternative if you stay to defend your house.
Reality
At this stage, there are no standards which specify how dugouts/bunkers should be constructed to be safe in bushfires, and when fire behaviour is extreme, the levels of radiant heat make it unsafe to leave a house to get to the shelter. Taking refuge in a cellar under a house is also unsafe, as if the house catches fire the floor is likely to collapse. The best bet is to make your house fire-safe with adequate preparation so that it can be actively defended even under Catastrophic conditions, or leave early if there is any doubt at all that the house can survive Catastrophic conditions.

Myth
Evacuation is the only way to survive fires.
Reality
It will always be safer to be away from a fire affected area than staying in the area during a fire. However, if people do not leave before a fire occurs, it may be a very dangerous option to leave at the last minute, and to be exposed to fire in a car or in the open. Many areas do not have any Neighbourhood Safer Places, and statistically, last minute evacuation is extremely dangerous as there is often nowhere safer than a house to evacuate to.

Myth
If Police or SES insist you evacuate, you must go.
Reality
If you have a 'pecuniary interest' (any financial interest) in your property, you cannot be forced to leave, even if Police believe you are in danger.

Myth
If there is a major fire in our area, Police traffic management points (or "roadblocks") won't allow anyone back into the area.
Reality
There will be several levels of traffic management points and entry into a fire affected area will be dependent on safety of people entering the area. Police will take advice about safety of the area from the Incident Controller who will have the final say about whether residents can return to their homes. Christmas Hills Fire Brigade aims to support the return of all residents into the area as soon as IT IS SAFE. You may be required to show some proof of local address (eg a Drivers licence with a local address or a Rates notice).