[ARRL-OK] Drought's Impact on Fire Danger

[KE5EXY]

Credit for this goes to the OCS Mesonet Ticker:

    How does Drought Impact Fire Danger?

   It's quite intuitive to assume that drought increases fire danger by
  drying out existing and dormant plant life. And that's a big part of
  drought's impact. Howver, one of the "invisible" enhancements to
  fire danger comes from drying of the subsurface. As the top few inches
  of soil become almost completely dry, the organic material becomes
  additional fuel for wildfire. The roots, dead bugs, dead worms, and 
  such in the subsurface literally burn along with the combustible
  material above the surface. This makes for more energetic, hotter
  fires. Moreover, they become much more difficult to extinguish.

  This process begins to impact fire conditions when the Keetch-Byram
  Drought Index (KBDI) exceeds about 200.  When the KBDI passes 400, the
  process becomes even more significant.  Above 600, this process is 
  profound.  Today's KBDI values are over 400 across more than half of
  the state:

        http://ticker.ocs.ou.edu/archive/20060102/latest.kbdi.png