SECTION 4: RISK ASSESSMENT
Weather conditions favorable to wildfire include drought, which increases flammability of surface fuels, and winds, which aid a wildfire‘s progress. The combination of wind, temperature, and humidity affects how fast wildland fires can spread. Rapid response can contain wildfires and limit their threat to property. Wake County experiences a variety of wildfire conditions found in the Keetch-Byram Drought Index, which is described in Table 4.80. The Keetch-Byram Drought Index (KBDI) for December 19, 2018 is shown in Figure 4.22 along with a Daily Fire Danger Estimate Adjective Rating for certain points across the state. The KBDI for Wake County at this time was below 100, and the Fire Danger Estimate for the nearby area was “Low.” Table 4.80 – Keetch-Byram Drought Index Fire Danger Rating System
Soil and fuel moisture are high. Most fuels will not readily ignite or burn. However, with sufficient sunlight and wind, cured grasses and some light surface fuels will burn in sports and patches. 200-400 Fires more readily burn and will carry across an area with no gaps. Heavier fuels will still not readily ignite and burn. Also, expect smoldering and the resulting smoke to carry into and possibly through the night. 400-600 Fire intensity begins to significantly increase. Fires will readily burn in all directions exposing mineral soils in some locations. Larger fuels may burn or smolder for several days creating possible smoke and control problems. 600-800 Fires will burn to mineral soil. Stumps will burn to the end of underground roots and spotting will be a major problem. Fires will burn through the night and heavier fuels will actively burn and contribute to fire intensity.
Figure 4.22 – Keetch-Byram Drought Index, December 2018
Source: USFS Wildland Fire Assessment System
Wake County Multi-Jurisdictional Hazard Mitigation Plan 2019
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