Ignition - Once all planning and preparation is complete, staff must monitor the weather and fuel conditions and determine when they are within the limits defined in the prescription. Regional resources exist that predict weather conditions such as wind direction and ceilings for smoke lofting several days ahead and at different times of day. Once the burn boss determines conditions fit the prescription, the operation can begin. Ignition is conducted with a drip torch, a tool designed to emit a small and controlled amount of a diesel and gasoline mixture through an end nozzle that is lit. The mixture combusts quickly as the fire begins to burn into the grass. The tool allows a firefighter to begin a prescribed fire in an even manner along the designated fire line, optimizing the ability of the fire to consume all of the vegetative fuel within the burn unit. This image shows the ignition of a head fire explained in a following slide.