Alert archive / Wyoming / Red Flag Warnings in 2026

Red Flag Warning 21, NWS Riverton, WY

August 7, 202612 counties in Wyoming

NWS Riverton, WY issued this red flag warning at Aug 7, 2026, 12:27 PM MDT for 12 counties in Wyoming. It took effect at Aug 8, 2026, 11:00 AM MDT. It was in force for 34 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Aug 7, 2026, 12:27 PM MDT (18:27 UTC)
In effect from: Aug 8, 2026, 11:00 AM MDT
Expired: Aug 9, 2026, 9:00 PM MDT
In force: 34 hr
Issued by: NWS Riverton, WY

Counties Big Horn County, WY, Fremont County, WY, Hot Springs County, WY, Johnson County, WY, Lincoln County, WY, Natrona County, WY, Park County, WY, Sublette County, WY, Sweetwater County, WY, Teton County, WY, Uinta County, WY, Washakie County, WY

The radar

The Riverton/Lander radar (KRIW), 35 km from the middle of the area, began a volume at 18:30 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The text

As transmitted.

710 
WWUS85 KRIW 071827
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
1227 PM MDT Fri Aug 7 2026

WYZ277>279-289-081230-
/O.NEW.KRIW.FW.W.0021.260808T1700Z-260810T0300Z/
/O.CON.KRIW.FW.W.0020.000000T0000Z-260808T0300Z/
Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
Granite/Green/Ferris/Rattlesnake Mountains-
1227 PM MDT Fri Aug 7 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS
EVENING...
...RED FLAG WARNING IN EFFECT FROM 11 AM SATURDAY TO 9 PM MDT
SUNDAY...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from 11 AM Saturday to 9 PM MDT
Sunday.

* IMPACTS: Low Humidities and Strong Gusty Winds could cause 
  erratic fire behavior. 

* AFFECTED AREA: 
  In Central WY Fire Zone....289.
  In Southwest WY Fire Zones...277...279.
  In West Central WY Fire Zone....278.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In Southwest WY...Sweetwater...Uinta.
  In West Central WY...Lincoln...Sublette.

* WIND: West 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: As low as 8 percent. Humidity recovery each night will
  remain below 40 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

WYZ288-081230-
/O.NEW.KRIW.FW.W.0021.260808T1700Z-260810T0300Z/
/O.CON.KRIW.FW.W.0020.000000T0000Z-260808T0300Z/
East Wind River Mountains/South Shoshone NF-
1227 PM MDT Fri Aug 7 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS
EVENING...
...RED FLAG WARNING IN EFFECT FROM 11 AM SATURDAY TO 9 PM MDT
SUNDAY...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from 11 AM Saturday to 9 PM MDT
Sunday.

* IMPACTS: Low Humidities and Strong Gusty Winds could cause 
  erratic fire behavior. 

* AFFECTED AREA: 
  In Central WY...Fire Weather Zone 288.

* COUNTIES AFFECTED: 
  In Central WY...Fremont.
  In West Central WY...Sublette.

* WIND: West 15 to 25 mph with gusts up to 40 mph.

* HUMIDITY: As low as 9 percent. Humidity recovery each night will
  remain below 40 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

WYZ140-275-276-280>283-285>287-300-081230-
/O.NEW.KRIW.FW.W.0021.260808T1700Z-260810T0300Z/
Yellowstone National Park-North Bighorn Basin/Worland BLM-
Cody Foothills-Natrona County/Casper BLM-Johnson County/Casper BLM-
South Bighorn Basin/Worland BLM-
Upper Wind River Basin/Wind River Basin-South Bighorn Mountains-
Absaroka Mountains/North Shoshone NF-Owl Creek Mountains-
Casper Mountain-
1227 PM MDT Fri Aug 7 2026

...RED FLAG WARNING IN EFFECT FROM 11 AM SATURDAY TO 9 PM MDT
SUNDAY...

The National Weather Service in Riverton has issued a Red Flag
Warning, which is in effect from 11 AM Saturday to 9 PM MDT
Sunday.

* IMPACTS: Low Humidities and Strong Gusty Winds could cause 
  erratic fire behavior. 

* AFFECTED AREA: 
  In Central WY Fire Zones...280...283...285...300.
  In North Central WY Fire Zones...275...276...281...282...287.
  In Northwest WY Fire Zones...140...286.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In North Central WY...Big Horn...Hot Springs...Johnson...Park
                        Washakie.
  In Northwest WY...Yellowstone National Park.

* WIND: Northwest 10 to 20 mph with gusts up to 30 mph.

* HUMIDITY: As low as 8 percent. Humidity recovery each night remains
  below 40 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

http://weather.gov/riverton

5 follow-up statements

224 
WWUS85 KRIW 080250
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
850 PM MDT Fri Aug 7 2026

WYZ277>279-289-081300-
/O.EXP.KRIW.FW.W.0020.000000T0000Z-260808T0300Z/
/O.CON.KRIW.FW.W.0021.260808T1700Z-260810T0300Z/
Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
Granite/Green/Ferris/Rattlesnake Mountains-
850 PM MDT Fri Aug 7 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM SATURDAY TO 9 PM
MDT SUNDAY...

* AFFECTED AREA: 
  In Central WY Fire Zone....289.
  In Southwest WY Fire Zones...277...279.
  In West Central WY Fire Zone....278.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In Southwest WY...Sweetwater...Uinta.
  In West Central WY...Lincoln...Sublette.

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty 
  Winds could cause erratic fire behavior. 

* WIND: West 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: As low as 8 percent. Humidity recovery each night will
  remain below 40 percent.

* TEMPERATURES: Lows in the low 50s to low 60s. Highs in the upper
  80s to upper 90s.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

WYZ288-081300-
/O.EXP.KRIW.FW.W.0020.000000T0000Z-260808T0300Z/
/O.CON.KRIW.FW.W.0021.260808T1700Z-260810T0300Z/
East Wind River Mountains/South Shoshone NF-
850 PM MDT Fri Aug 7 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM SATURDAY TO 9 PM
MDT SUNDAY...

* AFFECTED AREA: 
  In Central WY...Fire Weather Zone 288.

* COUNTIES AFFECTED: 
  In Central WY...Fremont.
  In West Central WY...Sublette.

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty 
  Winds could cause erratic fire behavior. 

* WIND: West 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: As low as 9 percent. Humidity recovery each night will
  remain below 40 percent.

* TEMPERATURES: Lows in the upper 40s to low 60s. Highs in the low 
  60s to low 80s.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

WYZ140-275-276-280>283-285>287-300-081300-
/O.CON.KRIW.FW.W.0021.260808T1700Z-260810T0300Z/
Yellowstone National Park-North Bighorn Basin/Worland BLM-
Cody Foothills-Natrona County/Casper BLM-Johnson County/Casper BLM-
South Bighorn Basin/Worland BLM-
Upper Wind River Basin/Wind River Basin-South Bighorn Mountains-
Absaroka Mountains/North Shoshone NF-Owl Creek Mountains-
Casper Mountain-
850 PM MDT Fri Aug 7 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM SATURDAY TO 9 PM
MDT SUNDAY...

* AFFECTED AREA: 
  In Central WY Fire Zones...280...283...285...300.
  In North Central WY Fire Zones...275...276...281...282...287.
  In Northwest WY Fire Zones...140...286.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona. 
  In North Central WY...Big Horn...Hot Springs...Johnson...Park
  ...Washakie. 
  In Northwest WY...Yellowstone National Park.

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty 
  Winds could cause erratic fire behavior. 

* WIND: Northwest 10 to 20 mph with gusts up to 30 mph.

* HUMIDITY: As low as 8 percent. Humidity recovery each night will
  remain below 40 percent.

* TEMPERATURES: Highs in the upper 70s to middle 80s at higher
  elevations and middle 90s to upper 90s at lower elevations. Lows
  in the upper 40s to upper 50s at higher elevations and upper 50s
  to low 60s at lower elevations.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

http://weather.gov/riverton

084 
WWUS85 KRIW 080633
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
1233 AM MDT Sat Aug 8 2026

WYZ140-275>283-285>289-300-090000-
/O.CON.KRIW.FW.W.0021.260808T1700Z-260810T0300Z/
Yellowstone National Park-North Bighorn Basin/Worland BLM-
Cody Foothills-Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
Natrona County/Casper BLM-Johnson County/Casper BLM-
South Bighorn Basin/Worland BLM-
Upper Wind River Basin/Wind River Basin-South Bighorn Mountains-
Absaroka Mountains/North Shoshone NF-Owl Creek Mountains-
East Wind River Mountains/South Shoshone NF-
Granite/Green/Ferris/Rattlesnake Mountains-Casper Mountain-
1233 AM MDT Sat Aug 8 2026

...RED FLAG WARNING REMAINS IN EFFECT FROM 11 AM THIS MORNING TO
9 PM MDT SUNDAY...

* AFFECTED AREA: 
  In Central WY Fire Zones...280...283...285...288...289...300.
  In North Central WY Fire Zones...275...276...281...282...287.
  In Northwest WY Fire Zones...140...286.
  In Southwest WY Fire Zones...277...279.
  In West Central WY Fire Zone....278.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In North Central WY...Big Horn...Hot Springs...Johnson...Park
                        Washakie.
  In Northwest WY...Yellowstone National Park.
  In Southwest WY...Sweetwater...Uinta.
  In West Central WY...Lincoln...Sublette.

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty 
  Winds could cause erratic fire behavior. 

* WIND: West 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: As low as 7 percent. Relative humidity recovery will be
  poor on Saturday night.

* TEMPERATURES: Highs in the 90s in the lower elevations. Highs in
  the 80s in the mountains.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

http://weather.gov/riverton

243 
WWUS85 KRIW 081737
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
1137 AM MDT Sat Aug 8 2026

WYZ140-275>283-285>289-300-091200-
/O.CON.KRIW.FW.W.0021.000000T0000Z-260810T0300Z/
Yellowstone National Park-North Bighorn Basin/Worland BLM-
Cody Foothills-Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
Natrona County/Casper BLM-Johnson County/Casper BLM-
South Bighorn Basin/Worland BLM-
Upper Wind River Basin/Wind River Basin-South Bighorn Mountains-
Absaroka Mountains/North Shoshone NF-Owl Creek Mountains-
East Wind River Mountains/South Shoshone NF-
Granite/Green/Ferris/Rattlesnake Mountains-Casper Mountain-
1137 AM MDT Sat Aug 8 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT SUNDAY...

* AFFECTED AREA: 
  In Central WY Fire Zones...280...283...285...288...289...300.
  In North Central WY Fire Zones...275...276...281...282...287.
  In Northwest WY Fire Zones...140...286.
  In Southwest WY Fire Zones...277...279.
  In West Central WY Fire Zone....278.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In North Central WY...Big Horn...Hot Springs...Johnson...Park
                        Washakie.
  In Northwest WY...Yellowstone National Park.
  In Southwest WY...Sweetwater...Uinta.
  In West Central WY...Lincoln...Sublette.

* IMPACTS: Low Humidities and Strong Gusty Winds could cause 
  erratic fire behavior. 

* WIND: West 10 to 20 mph with gusts up to 35 mph.

* HUMIDITY: As low as 7 percent. Humidity recovery will be poor
  tonight.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

http://weather.gov/riverton

912 
WWUS85 KRIW 090655
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
1255 AM MDT Sun Aug 9 2026

WYZ140-275>283-285>289-300-100300-
/O.CON.KRIW.FW.W.0021.000000T0000Z-260810T0300Z/
Yellowstone National Park-North Bighorn Basin/Worland BLM-
Cody Foothills-Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
Natrona County/Casper BLM-Johnson County/Casper BLM-
South Bighorn Basin/Worland BLM-
Upper Wind River Basin/Wind River Basin-South Bighorn Mountains-
Absaroka Mountains/North Shoshone NF-Owl Creek Mountains-
East Wind River Mountains/South Shoshone NF-
Granite/Green/Ferris/Rattlesnake Mountains-Casper Mountain-
1255 AM MDT Sun Aug 9 2026

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS
EVENING...

* AFFECTED AREA: 
  In Central WY Fire Zones...280...283...285...288...289...300.
  In North Central WY Fire Zones...275...276...281...282...287.
  In Northwest WY Fire Zones...140...286.
  In Southwest WY Fire Zones...277...279.
  In West Central WY Fire Zone....278.

* COUNTIES AFFECTED: 
  In Central WY...Fremont...Natrona.
  In North Central WY...Big Horn...Hot Springs...Johnson...Park
                        Washakie.
  In Northwest WY...Yellowstone National Park.
  In Southwest WY...Sweetwater...Uinta.
  In West Central WY...Lincoln...Sublette.

* IMPACTS: Low Humidities...Hot Temperatures...and Strong Gusty 
  Winds could cause erratic fire behavior. 

* WIND: West 10 to 20 mph with gusts up to 30 mph.

* HUMIDITY: As low as 8 percent.

* TEMPERATURES: Highs in the 90s in the lower elevations. Highs in
  the 80s in the mountains.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions are
either occurring now....or will shortly. A combination of strong
winds...low relative humidity...and warm temperatures can
contribute to extreme fire behavior.

&&

$$

http://weather.gov/riverton

120 
WWUS85 KRIW 100251
RFWRIW

URGENT - FIRE WEATHER MESSAGE
National Weather Service Riverton WY
851 PM MDT Sun Aug 9 2026

WYZ140-275>283-285>289-300-100400-
/O.EXP.KRIW.FW.W.0021.000000T0000Z-260810T0300Z/
Yellowstone National Park-North Bighorn Basin/Worland BLM-
Cody Foothills-Lincoln and Uinta Counties/Lower Elevations-
Upper Green River Basin/Rock Springs BLM-
Sweetwater County/Rock Springs BLM/Flaming Gorge NRA-
Natrona County/Casper BLM-Johnson County/Casper BLM-
South Bighorn Basin/Worland BLM-
Upper Wind River Basin/Wind River Basin-South Bighorn Mountains-
Absaroka Mountains/North Shoshone NF-Owl Creek Mountains-
East Wind River Mountains/South Shoshone NF-
Granite/Green/Ferris/Rattlesnake Mountains-Casper Mountain-
851 PM MDT Sun Aug 9 2026

...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING...

Winds have diminished in most locations even though relative
humidity values hover around the critical mark but soon to recover
some towards midnight and overnight in the 20 to 30 percent range
with continued lighter winds.

$$

http://weather.gov/riverton

The office that day

Everything else NWS Riverton, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 7, 1:12 AM MDT	Red Flag Warning	RIW	Fremont, Lincoln, Natrona, Sublette, Sweetwater, Uinta	20 hr

Nearby

Red Flag Warnings in Wyoming, 2026 Every red flag warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive.