The National Weather Service issued a special weather statement that warns of high fire danger in Cobb County and much of the rest of north Georgia in the afternoon and into the evening of Wednesday, March 8, 2023.
The reason for the high fire danger is low relative humidity.
What is in the statement?
The statement gives the following details:
...HIGH FIRE DANGER CONDITIONS THIS AFTERNOON INTO THE EVENING FOR
NORTH AND CENTRAL GEORGIA DUE TO LOW RELATIVE HUMIDITIES…
Relative Humidities of 25 percent or less can be expected for 4
or more hours this afternoon into the evening. Winds will be
easterly at 5 to 15 MPH.
With dry fuels, high fire danger conditions can be expected.
Please refer to your local burn permitting authorities
whether you may burn outdoors. If you do burn outside,
use extreme caution
What counties are affected?
The following counties are listed in the alert:
Dade, Walker, Catoosa, Whitfield, Murray, Fannin, Gilmer, Union, Towns, Chattooga, Gordon, Pickens, Dawson, Lumpkin, White, Floyd, Bartow, Cherokee, Forsyth, Hall, Banks, Jackson, Madison, Polk, Paulding, Cobb, North Fulton, Gwinnett, Barrow, Clarke, Oconee, Oglethorpe, Wilkes, Haralson, Carroll, Douglas, South Fulton, DeKalb, Rockdale, Walton, Newton, Morgan, Greene, Taliaferro, Heard, Coweta, Fayette, Clayton, Spalding, Henry, Butts, Jasper, Putnam, Hancock, Warren, Troup, Meriwether, Pike, Upson, Lamar, Monroe, Jones, Baldwin, Washington, Glascock, Jefferson, Harris, Talbot, Taylor, Crawford, Bibb, Twiggs, Wilkinson, Johnson, Emanuel, Muscogee, Chattahoochee, Marion, Schley, Macon, Peach, Houston, Bleckley, Laurens, Treutlen, Stewart, Webster, Sumter, Dooly, Crisp, Pulaski, Wilcox, Dodge, Telfair, Wheeler, Montgomery, Toombs,
Why does low relative humidity increase the danger of fire?
The National Park Service published the following explanation of why low relative humidity increases the danger of fires:
“Relative humidity is important because dead forest fuels and the air are always exchanging moisture. Low humidity takes moisture from the fuels, and fuels in turn, take moisture from the air when the humidity is high.
“Light fuels, such as grass and pine needles, gain and lose moisture quickly with changes in relative humidity. When the RH drops, fire behavior increases because these fine fuels become drier.
“Heavy fuels, on the other hand, respond to humidity changes more slowly. To see significant changes in heavy fuel moisture, there must be significant moisture, usually from more than a single storm.”
What precautions should be taken?
The National Weather Service recommends extreme caution if you do outdoor burning during high fire danger conditions, and that you check your local fire ordinances.
About the National Weather Service
The National Weather Service (NWS) is a part of the National Oceanic and Atmospheric Administration (NOAA).
The NWS describes its role as follows:
The National Weather Service (NWS) provides weather, water, and climate forecasts and warnings for the United States, its territories, adjacent waters and ocean areas, for the protection of life and property and the enhancement of the national economy. These services include Forecasts and Observations, Warnings, Impact-based Decision Support Services, and Education in an effort to build a Weather-Ready Nation. The ultimate goal is to have a society that is prepared for and responds to weather, water and climate events.