Chart 3: Nightime Dispersion Descriptor

Forecast Weather Event Recommendation
Stagnant Low level temperature inversion and
Stagnant air at night.
No burning.
Very Poor Rapid inversion set-up at sunset
and very light or calm wind.
Terminate burning in late afternoon
to allow smoke dispersal before sunset.
Poor Gradual inversion set-up overnight.
Light wind.
Terminate burning around dusk or 
shortly after sunset.
Fair Weak or no inversion set-up overnight.
Light to moderate wind.
Burning anytime.
Good No inversion. Moderate to strong and
gusty wind.
Burn with caution.
Possible adverse fire behavior.