Ember attack occurs when burning twigs and leaves are carried by the wind and land on or around houses. Embers are one of the principal causes of building damage during bushfires.
The entry of burning embers through unprotected openings is the principal cause of building damage during bushfires. These burning embers or "sparks" start small fires, often well before the main fire front arrives (traveling via wind) or also many hours after it has passed (through still burning despite the main, intense fire ceasing).
Embers can develop rapidly and may eventually engulf a whole building if left unattended.