Nighttime Smoke Dispersion
Prescribed burning, if properly applied, is the most economical means of eliminating the wildfire hazard of increased fuel loading that is created and left after each year of growth. If prescribed burns can be conducted at night, the number of hours available for burning is increased. To accomplish this practice, natural resource practitioners are requested that they voluntary comply with the NC SMP. Favorable wind conditions, direction and speed are essential in order to generate an acceptable rate of spread to the fire, dissipate its convective heat and disperse its smoke.
Under the present NC SMP, 20 ft wind speeds need to be equal to or better than 9 mph in order to conduct prescribed fire operations at night or early morning hours. Nighttime dispersion for smoke management is currently determined by wind speed as outlined in the table below.
|Nighttime Dispersion||Forecast Surface Wind||Interpretation|
|Stagnant||Near calm||Day burning needs to conclude 3 hrs. prior to sunset / no Burning at night|
|Very poor||2-4 MPH||Day burning needs to conclude 2 hrs. prior to sunset / no burning at night|
|Poor||5-8 MPH||Day burning needs to conclude prior to sunset / no Burning at night|
|Fair||9-12 MPH||nighttime burning permissible|
|Good||>12 MPH||nighttime burning permissible|
|Excellent||>14 MPH||nighttime burning permissible but dangerous|