Measurement in southern California chaparral prescribed fires show that the spread rates are increased by the effects of the turbulene on the flame velocities. The magnitude of the effect depends upon the fuel structure, local terrain, the atmospheric turbulence level (which may be modified by past fire behaior), and the wind speed of the air as it flows into the flame zone. In addition, the stoichiometric ratio in the flames may be important. Fire intensity may be similiarly affected. These effects combined to increase spread rates by a factor of 3 or 4 at ambient wind speeds of 5 meters/second. A logical extension of the theroy indicates increases in the spread rate by a factor of 20 may occur at ambient air speeds of 30 meters/second. The interactions are so complex and poorly understood that quantitative, accurate fire spread predictions are appearently almost impossible to make in southern California chaparral fuels at this time.