2-m Relatively Humidity and 20-ft Wind Speed Criteria for Fire Weather Headlines.  Also plotted are the nearby observations for significant wind-driven grassland wildfire starts in the region between 2006 and 2010.
2-m Relatively Humidity and 20-ft Wind Speed Criteria for Fire Weather Headlines.  Also plotted are the nearby observations for significant wind-driven grassland wildfire starts in the region between 2006 and 2010.

 

Red Flag Criteria are as follows:

  1. Average sustained winds of 20 mph or greater for the 20 foot level
  2. Wind gusts 35 mph or greater
  3. Relative Humidity of 15 percent or lower
  4. National Fire Danger Rating System (NFDRS) rating of high or higher
  5. 3 hour or greater duration
Starting on 3 January 2011, WFO Lubbock will also issue Fire Danger Statements. Fire Danger Statement Criteria are displayed graphically above and are as follows:
  • Average sustained winds of 10 to 20 mph at the 20 foot level and relative humidity of 0 to 10 percent

or

  • Average sustained winds of 15 to 20 mph at the 20 foot level and relative humidity of 10 to 15 percent

or

  • Average sustained winds of 25 mph or more at the 20 foot level and relative humidity of 15 to 20 percent

or

  • Average sustained winds of 30 mph or more at the 20 foot level and relative humidity of 20 to 25 percent 

The above wind and relative humidity criteria must also occur with:

1. Fuel dryness (100hr + ERC) of dry or worse (see GACC fuel dryness values from SPC)

2. Red Flag Threat Index (RFTI) of 1 or 2

3. Above normal forecast high temperatures


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