A backing fire is a fire moving against the wind. These fires are slow-moving and relatively cool. They create less smoke than either a flanking fire or a headfire and may combust fuels more efficiently. In a wildfire, these are generally not of concern because they are quite easy to extinguish. Usually, prescribed burns are supposed to be backing fires. Although backing fires are generally calm (i've stepped over them in grassland conditions before), they can not be ignored or taken for granted. A shift in the wind can turn a backing fire into a headfire in seconds. If you're near a backing fire and it looks like a wind shift is imminent (as indicated by shifts in the movement of smoke), you should get to the black as quickly as possible. This is the safest place to be during a fire.