Smoke Management Guidelines
Category 1:
No burning allowed, unless an adjustment from Category 1 to a Category 2 is made by utilizing the flow chart in the NC SMP SID under the section: Smoke Management Forecast - "Ventilation Index System the Permissible Adjustment from Burning Category (BC) 1 to Burning Category 2". This is permissible when Air Stagnation Advisory conditions are not predicted for a continuous 36 hour period following a planned prescribed fire ignition. Burning on BC 1 day is allowed if there are no smoke sensitive areas (SSA) downwind. When evaluating plume vectored direction under VIS and if there are no SSA, then burning fuel volume for a BC 2 is permissible.
Category 2:
Burning is usually only during the Daytime. Burning starts after the inversion is no longer present. If Nighttime Smoke Dispersion (NSD) is poor, burning will cease by sunset and when NSD is very poor, the active fire burning and significant smoke production will cease two hours prior to sunset. At these times the fire should be appreciably burned out with smoke production substantially ended. If the forecast NSD is fair or good, then burning past sunset is permissible.
Category 3:
If an inversion is present, then ignition of the burn must be delayed until after the inversion is no longer present. If NSD is predicted to be poor then burning will cease by sunset and when NSD is very poor the active fire burning and significant smoke production will cease two hours prior to sunset. If forecasted NSD is poor or very poor, only daytime burning is allowable. The fire should be appreciably burned out by the end of this time frame, with smoke production substantially ended.
If the NSD is fair or good, then daytime burning (all hours) and nighttime burning are permissible. If nighttime burning is allowed, ignition prior to receiving the new category day the following morning will be allowed based on the current category day. All burns (including those ignited earlier that morning) must comply with the new category day when issued.
Category 4:
Daytime burning (all hours) and night time burning is permissible with forecasted fair or good NSD. Night time ignitions prior to receiving the new category day the following morning will be based on the current category day. All burns (including those ignited earlier that morning) must comply with the new category day when issued.
If the forecasted NSD is poor, burning will cease by sunset and when the NSD is very poor, burning will cease two hours prior to sunset. If forecasted NSD is poor or very poor, then only daytime burning will be permitted. The fire should be appreciably burned out by the end of the respective time frames with smoke production substantially ended.
Category 5:
Daytime burning - (all hours) and night time burning is permissible with forecasted fair or good NSD. Night time ignitions prior to receiving the new category day the following morning will be based on the current category day. All burns (including those ignited earlier that morning) must comply with the new category day when issued.
If the predicted NSD is poor then, burning will cease by sunset and when the NSD is very poor, burning will cease two hours prior to sunset. If forecasted NSD is poor or very poor, then only daytime burning will be permitted. The fire should be appreciably burned out by the end of the respective time frames with smoke production substantially ended.
Organic Material - Residual Burning
When organic material is ignited during prescribed burning activities, and the material continues to burn, a daily evaluation will be made to estimate the acres continuing to burn within a given 16,000-acre block and approximate daily tonnage that will be consumed. The standard daily burning rate of undisturbed organic material is 16 tons/acre/day. This assumes that one solid acre burns at the same rate of approximately one inch per day. Adjustments to the daily burning rate of organic material and to the actual number of acres on fire are necessary to actually assess the impact or residual burning within each 16,000-acre block. The tonnage derived from residual burning will be subtracted from the available total tonnage each day to determine the adjusted tonnage that can burned within the 16,000 acre block.
Allowable Tonnage and Fuel Loading Tables (PDF)