Victoria is one of the most fire-prone areas in the world. Bushfires and grassfires start quickly, often without warning and they can threaten lives and properties within minutes.
There’s no questioning the facts. During a fire, embers can travel up to 40 kilometres ahead of the fire front and fire speeds can reach over 25 kilometres per hour.
Produced with the assistance of the CSIRO Bushfire Behaviour and Risks team, and shot on location at the CSIRO Pyrotron in Canberra, the Facts of Fire series explores the serious dangers Victorians face annually from fire, including ember attack, spot fires, radiant heat, wind speed and grassfires.
Remember, on high-risk fire days, leaving early before a fire starts, is always the safest option.
Embers
Fire embers are glowing hot and remain after or precede a fire. Embers are often as hot as the fire which created them.
During a fire, embers can travel up to 40 kilometres, starting spot fires well ahead of the fire-front – often without warning.
There’s no questioning the facts, leaving a high fire-risk area early is always the safest option.
Spot fires
The term spot fire describes a fire ignited outside of a burning unit as a result of a windborne ember (sometimes referred to as a firebrand).
Spot fires can start new bushfires well ahead of the main fire front.
In large fires, there’s the potential for many spot fires to start and quickly join together, blocking a safe escape.
There’s no questioning the facts, your garden hose is no match for spot fires so leaving a high fire-risk area early is always the safest option.
Wind speed
A fire will burn faster uphill. This is because the flames can easily reach more unburnt material (like grass) in front of the fire. Radiant heat pre-heats the grass in front of the fire, making it even more flammable.
In Victoria, most high-risk fire areas are not flat, so fires can spread and become out of control quickly.
On a 10-degree slope, fire will travel twice as fast as a fire on flat ground in the same conditions, and on a 20-degree slope, it will travel four times as fast.
There’s no questioning the facts, if you live in high fire-risk areas, leaving early is always the safest option.
Radiant heat
During a bushfire, the atmosphere will literally feel like hell on earth.
Flame temperatures can reach up to 11000C and radiant heat fluxes high enough to vaporise vegetation, only adding speed to the scorching hot flames.
There’s no questioning the facts, if you are stuck in a bushfire, your chances of survival are slim. Leaving early is always the safest option.
Grassfires
Fires don’t just happen in the country, if you live near grasslands, parks or paddocks, you are at risk of grassfires.
Grassfires can be just as dangerous as bushfires – grass is the most predominant fuel type in Australia. It ignites very quickly, burns rapidly and can travel at speeds of up to 25 Kilometres per hour.
In rural areas, if a grassfire starts, you should leave as early as possible and move to built up areas well away from the fire.
If you live directly next to grasslands in urban areas across metropolitan Melbourne or in large regional centres and a fire starts, walk at least two streets back and monitor conditions. If you are already two or three streets away, remain where you are and stay alert. Don’t drive, visibility may be poor, accidents are likely, and you could block emergency services.
There’s no questioning the facts, even urban areas can be at risk.
