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Scale of threat levels

for South Central and Southeast Wisconsin
Fire Weather Threat
Hazard Map Threat Levels Safety & Impact

The "Fire Weather Hazard Map" depicts the local threat (weather-related only) of potential wild fires for specified areas.  It is largely based on the character of surface relative humidity (the effects on fuel moisture), 20-foot wind speed (the effects on wild fire growth, spread, and spotting), and lightning (a natural ignition source).

Fire Weather
Threat Level

Threat Level Descriptions

Extreme

"An Extreme Threat to Life and Property from Existing or Potential Wildfires Due to Weather."

An extreme likelihood (36% or greater probability) that wildfire weather conditions meet or exceed Red Flag criteria (see definition below) .  Prevailing winds 15 mph or greater; lightning storms forecast.

High

"A High Threat to Life and Property from Existing or Potential Wildfires Due to Weather."

A high likelihood (26% to 35% or greater probability) that wildfire weather conditions meet or exceed Red Flag criteria (see definition below) . Prevailing winds 15 mph or greater; no lightning storms forecast.

Moderate

"A Moderate Threat to Life and Property from Existing or Potential Wildfires Due to Weather."

A moderate likelihood (16% to 25% or greater probability) that wildfire weather conditions meet or exceed Red Flag criteria (see definition below) .  Prevailing winds remain less than 15 mph; lightning storms forecast. 

Low

"A Low Threat to Life and Property from Existing or Potential Wildfires Due to Weather."

A low likelihood (6% to 15% or greater probability) that wildfire weather conditions meet or exceed Red Flag criteria (see definition below) .  Prevailing winds remain less than 15 mph; no lightning storms forecast.

Very Low
" A Very Low Threat to Life and Property from Existing or Potential Wildfires Due to Weather."

A very low likelihood (2% to 5% or greater probability) that wildfire weather conditions meet or exceed Red Flag criteria (see definition below). Prevailing winds less than 15 mph.

Non-Threatening
" No Discernable Threat to Life and Property from Existing or Potential Wildfires Due to Weather."

Wildfire weather conditions are below Red Flag criteria and non-threatening.     

Note: In Wisconsin, "Red Flag" conditions exist in a given area when the following are met:
1) The relative humidity is 25 percent or less.
2) Sustained 10-minute winds at the 20 foot level are at or above 15 mph.
3) Temperature equal to or greater than 750 F
Plus dry fuels are required and this is coordinated with the WDNR and USFS.

Determining Likelihood

  • National Weather Service
  • Milwaukee/Sullivan, WI Weather Forecast Office
  • N3533 Hardscrabble Road
  • Dousman, WI 53118
  • 262-965-2074
  • Page Author: MKX Webmaster
  • Web Master's E-mail: w-mkx.webmaster@noaa.gov
  • Page last modified: 2-Nov-2005 10:23 PM UTC
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