National Wildfire Coordinating Group

4.2 Flame Height

Flame height is the average height of flames as measured vertically, up and down. It may be less than flame length if the flames are angled in the horizontal direction, backward or forward. 
 

photograph showing flame height
 

Flame height can be approximated by comparing the flame to an object of known dimensions, such as a pole, fencepost, or firefighter.