Fine, dead vegetation such as dry grass, leaves, and pine needles that has a high surface-area-to-volume ratio. These fuels take approximately one hour for their moisture content to reach equilibrium with the surrounding air. Because they dry out so quickly, they are highly flammable and act as the primary ignition source and carrier for fast-moving surface fires.
Heard on the job
Humidity is dropping fast and we have continuous one-hour fuel ahead of the main front, so expect fire behavior to pick up.
Insider tip
When assessing fire danger, wildland firefighters watch one-hour fuels closely because they dictate the immediate rate of spread.
Also heard as
- fine fuels
- flashy fuels