Fine, dead wildland vegetation such as cured grass, dry leaves, pine needles, and small twigs that respond quickly to changes in moisture and temperature. Because they have a high surface-area-to-volume ratio, these materials dry out fast and ignite with minimal heat. They are the primary carrier of initial fire spread and dictate how quickly a wildland incident expands.
We've a lot of flash fuel in that drainage, so expect the fire to run fast if the wind shifts.
Flash fuels are often categorized as one-hour timelag fuels because their moisture content reaches equilibrium with the surrounding air in roughly an hour.
Also heard as
- fine fuel
- light fuel
Related terms
One-hour fuel
Dead vegetation less than a quarter-inch in diameter that reacts rapidly to changes in relative humidity.
Slopover
A fire edge that crosses a control line or natural barrier.
Firebreak
A gap in vegetation or other combustible material that acts as a barrier to slow or stop the progress of a wildfire.