[1] Eucalyptus bark is generally considered the most dangerous source in Australia.
This led to the definition of a categorical classification (Bark Hazard)[2] used to evaluate the potential threat of ember attack.
The Stringybark species of Eucalypt is particularly notorious for contributing large flaming sections of bark that due to their size, weight and shape, can be carried up to several kilometres away.
[6] Direct ignition of structures due to ember is possible, for example: However, the majority of property loss happens due to secondary ignitions, for example: Embers commonly cause house loss up to 500 meters from the fire front,[7] and in exceptional circumstances up to kilometers[8] In Australia, evaporative air conditioners are known to ignite from ember attack.
Ember attack causes the filter pads from evaporative AC to ignite, and the fire spreads through the roof space destroying the home.