concept

Firebrand spotting

How a fire crosses a gap without any continuous flame on the ground. The convective plume lofts burning fragments - bark plates, twigs, curled leaves - and upper winds carry them downwind to land and start fresh fires hundreds of metres to several kilometres ahead of the main front. It is the dominant mechanism by which fires cross rivers, cleared firebreaks and the defensible space around settlements, because a barrier that stops surface spread does nothing about something airborne. The consequence is that real fire fronts usually advance in leaps rather than creeping evenly.