Effective mid-flame wind speed

n. The magnitude of the resultant spread vector expressed as an equivalent no-slope mid-flame wind speed.


  • Discussion


The effective mid-flame wind speed is calculated in an algebraic equation involving slope steepness, wind speed, and wind direction. In the Rothermel (1972) surface fire spread model, the effect of mid-flame wind speed is expressed as the wind coefficient, and the effect of slope steepness is expressed as the slope factor.


  • Units


    Preferred units for wind speed are km/hr in technical reports and papers. Fire Management in the United States still uses the English units mi/hr. Engineering and physics applications may use units of m/s or ft/s. See the following wind speed units conversion table for conversion factors.


  • References

    • Rothermel, R.C. 1972. A mathematical model for predicting fire spread in wildland fuels. Res. Pap. INT-115. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 42 p.


  • See Also

  • Notes

    • Author 

      Joe Scott, Research Forester

      Systems for Environmental Management