Myths about bushfires often lead to risky decisions or a false sense of security. This article busts the most common bushfire myths to help you make better bushfire safety decisions.
Myth Buster: Not necessarily. Dense tree canopies can reduce wind speeds and therefore the speed of a bushfire, and shield embers.
Reducing the amount of vegetation close to your house, reducing fine fuel and creating places with no vegetation has the biggest influence on reducing the impact of a bushfire (Surface, Near Surface and Elevated fuel - watch Kevin Tolhurst’s commentary in the Fuel Hazard Guide 2010)
Myth Buster: A running crown fire can only continue when a high amount of Surface, Near Surface and Elevated fuel are present. Crown fires in eucalypt forests are nearly always associated with uphill runs of fire.
Myth Buster: Fire fronts move faster in thinned forests and open grassland.
Myth Buster: The configuration of various plants comprising fine fuel provides a pathway ladder for a fire near the ground to ignite the canopy of a tree. If there is plenty of fuel at ground level the fire can spread to the canopy creating a crown fire. Cypress hedges are an example of a continuous ladder of fuel from the ground to the top of the tree.
Myth Buster: Fine fuel can be dead material thinner than a pencil or live material thinner than a match.
Myth Buster: The most prevalent cause of house loss is by embers entering the building through gaps greater than 2mm or by embers igniting combustible elements.
Myth Buster: Embers can travel hundreds of metres and in some cases 30km from their source. Many houses are lost due to embers igniting fine fuel which then ignites nearby structures or combustible elements like timber fences or retaining walls near a house. The radiant heat from the consequential fire ignites the house.
Myth Buster: Embers can ignite fine fuel near containers of volatile fuels like petrol, farm chemicals and solvent liquids stored below gapped verandahs or underneath decks, near to or under the house.
Myth Buster: Embers ignite fine fuel near combustible elements like timber retaining walls, timber fences, organic wood mulch, timber garden edges, steps, decks, stored firewood and posts. The consequential fire destroys homes and structures.
Myth Buster: Bark on the trunks of trees is the main source of embers. Other fine fuel i.e. leaves and seed pods also produce embers.
Myth Buster: A strategic approach of reviewing, reducing, removing, separating, replacing, and disposing of vegetation reduces risk.
Myth Buster: Reducing vegetation around the house may reduce risk but not eliminate it.
Myth Buster: Zone Zero, the 1.5 metre wide area immediately next to the structure’s external walls, deck or verandah is the most critical area. Eliminate all combustible materials within this zone (BRI webinar Harden you home for bushfire 18 September 2025).
Myth Buster: Organic wood mulch is one of the worst materials to have within 10m of a house or structure. It’s a recipe for a disaster. Mulch is easily ignited by embers and is very difficult to extinguish. Homes were destroyed in 2009 well after the fire front passed through when mulch, previously thought to have been extinguished, reignited.
Myth Buster: One person’s fuel is another person’s risk. Depending on the separation from your adjoining neighbor/s, burning vegetation or a burning structure on your property could provide a radiant heat source that affects your neighbour’s home that could lead to an urban conflagration fire with widespread impact similar to a set of dominos e.g. Canberra 2003, Marysville 2009, Wye River 2015 and Los Angeles 2025.
Myth Buster: Only 20% of house fires involve a fire front (BRI webinar Reduce your house and property risk 21 July 2021).
Myth Buster: Depending on weather conditions and topography, embers can travel in different directions, including from a direction other than the prevailing wind. Wind speed and direction can change at any moment. Additionally, higher altitude winds can affect where embers travel. Many accounts describe multiple wind direction changes during a fire including towards the prevailing wind.
Myth Buster: The leeward side of a structure is also at risk due to wind and terrain interaction (BRI webinar Grass fire and bushfire behavior 13 September 2023).
Myth Buster: The leeward side of a landscape ridge is also a risk. Embers can start a fire on the leeward side of the hill then burn up the slope towards the fire front (BRI webinar Grass fire and bushfire behavior 13 September 2023).
Myth Buster: Embers can start a fire on the leeward side of the hill where your house is located then burn up the slope towards the fire front and affect any house in the landscape e.g. Wye River 2015.
Myth Buster: Grass fires have been lethal to people. (BRI webinar Grass fire and bushfire behavior 13 September 2023).
Myth Buster: The average rate of spread of a grass fire is 20km/h, compared with a possible 12km/h for a forest fire.
The rate of spread of a grass fire is approximately 20% of the average wind speed.
If you double the wind speed you double the rate of spread of a grass fire (BRI webinar Grass fire and bushfire behaviour 13 September 2023).
Myth Buster: In many locations bad fire weather days are associated with a wind change
Before the front arrives strong winds bring hot, dry air from the north-west.
Before the arrival of the wind change. A fire under the prevailing north-westerly wind burns towards the south-east.
After the arrival of the front the wind comes from the south-west. The previous flank (side) of the fire becomes the new much longer fire front. The fire spreads rapidly to the north-east.
Experience has shown the majority of fatalities and house loss occurs during and immediately after the wind change (BRI webinar Grass fire and bushfire behavior 13 September 2023).
Some of the most devastating fires in Australia's history - Black Saturday (2009), Ash Wednesday (1983) and Black Friday (1939) occurred in hauntingly similar conditions - a very strong high pressure system (high temperature, low humidity and strong north or north-west wind), and an approaching cold front (a strong south-west wind change with associated violent, erratic and unpredictable winds).
