1-100 Hour Fuel Moistures

Moisture content of fuel (dead woody fuel) is the mass of water within the fuel particle expressed as a percentage of the fuel particle’s oven-dry mass.

Defining fuel moistures for fuels of various sizes.

Fuel diameter (inches)	Hourly Designation	Brief Description
< 1/4	1-Hr	Fine flashy fuels that respond quickly to weather changes. Computed from observation time temperature, humidity, and cloudiness.
1/4 - 1	10-Hr	Computed from observation time temperature, humidity, and cloudiness. Alternatively, these can be an observed value from a standard set of "10-Hr Fuel Sticks" that are weighed as part of the fire weather observation.
1 - 3	100-Hr	Computed from 24-hour average boundary condition composed of day length, hours of rain, and daily temperature/humidity ranges.