Wildfire Knowledge Graph · Fuels & Weather
A material change in wind direction that can rapidly alter head-fire orientation, spread direction and exposure.
In plain language
A material change in wind direction that can rapidly alter head-fire orientation, spread direction and exposure.
Why it matters
Wind Shift is useful because it separates one specific part of wildfire behaviour, exposure, operations or evidence from nearby concepts that can otherwise be mixed together.
What is a wind shift in wildfire?
A wind shift is a meaningful change in wind direction over a relatively short period. In NWCG ground-observation terminology, a shift is a change of at least 45 degrees in the direction of a significant wind occurring in a short time frame.
Why a wind shift matters to a wildfire
Wildfire spread direction is strongly influenced by wind. When the wind turns, a previously less active flank can become aligned with the new wind direction and develop into a new head of the fire. Smoke transport, ember trajectories and exposure can change at the same time.
- The fastest-spreading sector can move to another part of the perimeter.
- Existing control lines may face a different direction of fire approach.
- Spotting direction and smoke transport can change rapidly.
- Observed fire behavior should always be interpreted with a timestamp and wind context.
Official reference: NWCG — wind shift (ground observation).
Related: Head, Flank and Rear of a Wildfire · Wind Speed.