Drought Condition Awareness
To view your county's KBDI current number, go to http://twc.tamu.edu
As the saying goes here in Texas, "If you don't like the weather, wait until tomorrow!" Awareness is the key to a safe and fun filled summer.
Travel plans should begin with a weather forecast for the areas you will be traveling through and to. Emergency travel kits should provide safety equipment for a vehicle breakdown, fire extinguisher, sunburns, bug bites, heat exhaustion and dehydration.
Flash flooding quickly provides problems for travelers as low water crossings fill with swift water run-off. Be familiar with the roads you are traveling, especially at night, and always TURN AROUND, DON'T DROWN.
While flooding occurs quickly, Texas also goes from flood to drought in a matter of a week. The Cumulative Severity Index (CSI) or Keetch-Byram Drought Index (KBDI) is a continuous reference scale for estimating the dryness of the soil and duff layers. This system was originally developed for the southeastern United States and is based primarily on recent rainfall patterns.
This mathematical system for relating current and recent weather conditions to potential or expected fire behavior results in a drought index number ranging from 0 to 800. This number accurately describes the amount of moisture that is missing; a rating of 0 defines a point of no moisture deficiency and 800 defines the maximum drought possible.
Long periods of drought (high KBDI) influence fire intensity since more fuel is available for combustion (i.e. fuels have a lower moisture content). In addition, dry organic materials in the soil can lead to increased difficulty in fire suppression. High values of the KBDI are an indication that conditions are favorable for the occurrence and spread of wildfires, but drought is not by itself a prerequisite for wildfires. Other weather factors, such as wind, temperature, relative humidity and atmospheric stability, play a major role in determining the actual fire danger.
These KBDI numbers correlate with potential fire behavior as follows:
0-200 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 spots 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.
Back to top |
