(a) For the purpose of this section the following definitions shall apply: (1) "Restricted fireworks" means only those items classified under 49 C.F.R. Sec 173.100(r)(2) (10-1-86 edition), as "skyrockets with sticks" and "missiles with fins". (2) "Drought conditions" shall mean the existence immediately proceeding or during the fireworks season of a long-term deficit of moisture creating a typically severe conditions with increased wildfire occurrence as defined by the Texas Forest Service through the use of the Keetch-Bryam Drought Index, or when such index is not available, through a comparable measurement which takes into consideration the burning index, spread component, or ignition component for that particular area.
(b) (1) The Texas Forest Service in the ordinary course of its activities shall determine whether drought conditions, as defined under Subsection (a)(2), exist in all or part of any county requesting such determination. The Texas Forest Service shall make available the measurement index guidelines that determine whether a particular area is in drought condition. Following any determination that such drought conditions exist, Texas Forest Service shall notify said county or counties when such drought conditions no longer exist.
(c) Upon a determination under this section that drought conditions exist within all or part of a specified county, the commissioners court of such county by order may prohibit or restrict the sale or use of restricted fireworks in all or a portion of the unincorporated area of the county where drought conditions have been determined to exist. In addition, during the December fireworks season, the commissioners court of a county by order may restrict or prohibit the sale or use of restricted fireworks in specified areas when conditions on rural acreage in the county not under cultivation for a period of at least 12 months are determined to be extremely hazardous for the danger of fire because of high grass or dry vegetation.
(d) To facilitate compliance with an order adopted under Subsection (c), the order must be adopted before: (1) June 15 of each year for the Fourth of July fireworks season; and (2) December 15 of each year for the December fireworks season.
(e) An order issued under this section shall expire upon determination as provided under Subsection (b) that such drought conditions no longer exist.
§ 352.081. Regulation Of Outdoor Burning
(a) In this section, "drought conditions" means the existence of a long-term deficit of moisture creating atypically severe conditions with increased wildfire occurrence as defined by the Texas Forest Service through the use of the Keetch-Byram Drought Index or, when that index is not available, through the use of a comparable measurement that takes into consideration the burning index, spread component, or ignition component for the particular area.
(b) On the request of the commissioners court of a county, the Texas Forest Service shall determine whether drought conditions exist in all or part of the county. The Texas Forest Service shall make available the measurement index guidelines that determine whether a particular area is in drought condition. Following a determination that drought conditions exist, the Texas Forest Service shall notify the county when drought conditions no longer exist. The Texas Forest Service may accept donations of equipment or funds as necessary to aid the Texas Forest Service in carrying out this section.
(c) The commissioners court of a county by order may prohibit or restrict outdoor burning in general or outdoor burning of a particular substance in all or part of the unincorporated area of the county if: (1) drought conditions have been determined to exist as provided by Subsection (b); or (2) the commissioners court makes a finding that circumstances present in all or part of the unincorporated area create a public safety hazard that would be exacerbated by outdoor burning. (d) An order adopted under this section must specify the period during which outdoor burning is prohibited or restricted. The period may not extend beyond the 90th day after the date the order is adopted. A commissioners court may adopt an order under this section that takes effect on the expiration of a previous order adopted under this section. (e) An order adopted under this section expires, as applicable, on the date: (1) a determination is made under Subsection (b) that drought conditions no longer exist; or (2) a determination is made by the commissioners court that the circumstances identified under Subsection (c)(2) no longer exist.
Keetch-Byram Drought Index (KBDI)
Is an index used in determining forest fire potential - John J. Keetch and George Bryam designed the drought index specifically for fire potential assessment. It is a continuous index, relating to the flammability of organic material in the ground. The drought index is based on a daily water balance, where a drought factor is balanced with precipitation and soil moisture (assumed to have a maximum storage capacity of 8-inches) and is expressed in hundredths of an inch of soil moisture depletion.
The drought index ranges from 0 to 800, where a drought index of 0 represents no moisture depletion, and an index of 800 represents absolutely dry conditions. Presently, this index is derived from ground based estimates of temperature and precipitation derived from weather stations and interpolated manually by experts at the Texas Forest Service (TFS) for counties across the state.
At any point along the scale, the index number indicates the amount of net rainfall that is required to reduce the index to zero, or saturation. The inputs for KBDI are weather station latitude, mean annual precipitation, maximum dry bulb temperature, and the last 24 hours of rainfall. Reduction in drought occurs only when rainfall exceeds 0.20 inches (called net rainfall).
KBDI levels and its relationship to expected fire potential are reflected in the following table:
KBDI = 0 - 200: Soil moisture and large class fuel moistures are high and do not contribute much to fire intensity.
KBDI = 200 - 400: Lower litter and duff layers are drying and beginning to contribute to fire intensity.
KBDI = 400 - 600: Lower litter and duff layers contribute to fire intensity and will burn actively.
KBDI = 600 - 800: Often associated with more severe drought with increased wildfire occurrence. Intense, deep-burning fires with significant downwind spotting can be expected. Live fuels can also be expected to burn actively at these levels.