Photograph: Luis Ascui/Getty Images
Ember attacks, also known as firebrand blizzards, have been a feature of the recent Australian wildfires. They occur when wind carries masses of burning vegetation fragments ahead of the main fire, starting many smaller fires.
Eucalyptus, common in most parts of Australia, is known as gum tree for its sticky and highly flammable resin. Eucalyptus bark easily peels off into small fragments, so it produces especially severe ember attacks. In one incident on 1 January, firefighters were trapped in their vehicle by a storm of flaming debris.
Ember attacks are a particular hazard for houses. One factor is air conditioning systems with filters made of cellulose, which can catch fire when the conditioner draws in burning material. Air conditioners are often in the attic, so the resulting fire may be difficult to put out and spreads rapidly to the rest of the house. Fireproof vent screens are one solution. A single ember may not be dangerous, but houses often have places where falling debris piles up, such as gutters or crevices in decking. This build-up may reach a critical point where it is hot enough to start a new fire.
Australian researchers are now using weather radar to attempt to track burning debris carried on the wind and help predict areas at risk from ember attack.
