Dead fuels consisting of roundwood 1/4 to l-inch (0.6 to 2.5 cm) in diameter and, very roughly, the layer of litter extending from immediately below the surface to 3/4 inch (1.9 cm) below the surface.

The moisture content of the l0-hour timelag roundwood fuels.

Extensive, thick blanket of smoke spreading more or less horizontally from a fire.

A method of determining winds aloft by periodically reading the elevation and azimuth angles of a theodolite, usually at one-minute intervals, while tracking the ascent of a small free-lift balloon. A PIBAL is commonly used for constructing a wind profile. 

As resources are ordered to respond to an incident, Request Numbers (occasionally referred to as a resource order number) are issued. The order number includes the incident number, an alpha character (S = Supplies, E = Equipment, O = Overhead, A = Aircraft, C = Crews, M = Agency Provided Medical Care) followed by a sequential number.

The ICS management process in which the on-scene incident commander at a specified time hands off command responsibilities to the incident commander that will be taking over incident command.

Large glowing firebrands are carried high into the convection column and then fall out downwind beyond the main fire starting new fires. Such spotting can easily occur 1/4 mile or more from the firebrand's source.

The ICS Section that collects, evaluates, and disseminates operational information related to the incident and for the development of the IAP. This section also maintains information on the current/forecasted situation and on the status of resources assigned to the incident.

Any wildfire that requires fire suppression to protect natural resources or values associated with natural resources, or is destructive to natural resources.

A category used to describe the diameter of down dead woody fuels. Fuels within the same size class are assumed to have similar wetting and drying properties, and to preheat and ignite at similar rates during the combustion process.