Basic concepts of wild land fire Questions and answers 100% verified

origin - AnswerThe origin is the area where the fire started. It is also the point from which the fire spreads, depending on the fuels present and the effects of wind and slope. When the fire is human-caused, you often find the origin next to a trail, road, or highway, but a lightning strike or campfire can result in a very inaccessible point of origin. Protect the area of origin for subsequent investigation of fire cause whenever possible. head - AnswerThe head is the part of a wild land fire with the greatest forward rate of spread (ROS). Because wind and slope affect the rate and direction of spread, the head is normally either on the edge of a fire opposite to the direction from which the wind is blowing or it is toward the upper part of a slope. The head of a fire often burns intensely and may move with alarming speed. Some large fires may have multiple heads. Ultimately, you have to control the head(s) and prevent the formation of new heads to suppress a wildland fire. fingers - AnswerFingers are typically long, narrow strips of fire that extend from the main body of a fire. They form: When a fire burns into mixed fuels; slowing in heavy fuel, but spreading quickly in light fuels Due to variations in terrain or wind direction When the head is split by natural features such as fields, water, or rock outcroppings Caution: Uncontrolled fingers may form new heads. If possible, knock them down when they're small and manageable. pocket - AnswerA Pocket is the unburned area between the main fire and any fingers. perimeter - AnswerThe perimeter is the outer boundary—or the distance around the outside edge—of the burning or burned area. Also commonly called the fire edge, don't confuse the perimeter with the control line (an inclusive term for all constructed or natural barriers and treated fire edges used to control a fire) or fireline (the part of the control line that is constructed by firefighters). Obviously, the fire's perimeter continues to grow until you get it controlled and extinguished. flanks - AnswerThe flanks are the sides of a wildland fire, roughly parallel to the main direction of fire spread. Flanks are identified as either left or right as you are looking from the heel of a fire toward the head. Control flanks as soon as possible, because: A shift in wind direction may quickly change a flank into a head Fingers often extend from flanks rear - AnswerThe rear, or heel, of a wildland fire is the end opposite the head—that is, relatively closer to the point of origin than to the head. Because fire at the heel usually burns into any prevailing wind, it generally: