Alert archive / Nevada / Red Flag Warnings in 2021

Red Flag Warning 17, NWS Reno, NV

September 17, 20217 counties in Nevada; Lassen County, Modoc County, California

NWS Reno, NV issued this red flag warning at Sep 17, 2021, 11:35 AM PDT for 7 counties in Nevada; Lassen County, Modoc County, California. It took effect at Sep 18, 2021, 1:00 PM PDT. It was in force for 7 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
Sep 17, 2021, 11:35 AM PDT (18:35 UTC)
In effect from
Sep 18, 2021, 1:00 PM PDT
Expired
Sep 18, 2021, 8:00 PM PDT
In force
7 hr
Issued by
NWS Reno, NV

Counties Lassen County, CA, Modoc County, CA, Churchill County, NV, Douglas County, NV, Lyon County, NV, Mineral County, NV, Pershing County, NV, Storey County, NV, Washoe County, NV

The radar

The Reno radar (KRGX), 15 km from the middle of the area, began a volume at 18:38 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 nearest sounding before it

Reno, NV (KREV), launched 12:00Z, 6.6 hours before the alert went out and 107 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Reno, NV at 12:00Z on 2021-09-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Reno, NV at 12:00Z on 2021-09-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -11 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2639 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
-11 m²/s²
0-3 km storm-relative helicity
-7 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

927 
WWUS85 KREV 171835
RFWREV

URGENT - FIRE WEATHER MESSAGE
National Weather Service Reno NV
1135 AM PDT Fri Sep 17 2021

NVZ429-182300-
/O.UPG.KREV.FW.A.0016.210918T2000Z-210919T0300Z/
/O.NEW.KREV.FW.W.0017.210918T2000Z-210919T0300Z/
/O.CON.KREV.FW.A.0017.210919T1900Z-210920T0300Z/
Lahontan Basin including Churchill and Eastern Mineral Counties-
1135 AM PDT Fri Sep 17 2021

...RED FLAG WARNING IN EFFECT FROM 1 PM TO 8 PM PDT SATURDAY FOR
GUSTY WINDS AND LOW HUMIDITY FOR THE LAHONTAN BASIN PRIMARILY
NORTH OF US-50... 

...FIRE WEATHER WATCH REMAINS IN EFFECT FROM SUNDAY AFTERNOON 
THROUGH SUNDAY EVENING FOR GUSTY WINDS AND LOW HUMIDITY PRIMARILY 
SOUTH OF US-50...

The National Weather Service in Reno has issued a Red Flag
Warning for gusty winds and low humidity, which is in effect from
1 PM to 8 PM PDT Saturday. The Fire Weather Watch is no longer in
effect.

* Changes...Upgraded to a Red Flag Warning on Sunday.

* Affected Area...Fire Zone 429 Lahontan Basin including 
  Churchill and Eastern Mineral Counties.

* Winds...Southwest to west 15 to 25 mph with gusts to 40 mph
  Saturday, shifting to northwest 10 to 20 mph with gusts to 35
  mph Sunday afternoon.

* Humidity...Saturday: 7-12%. Sunday: 15-20% north of US-50, 10- 
  15% south of US-50.

* Duration...4-7 hours Saturday. 2-4 hours Sunday.

* Impacts...The combination of gusty winds and low humidity can 
  cause fire to rapidly grow in size and intensity before first 
  responders can contain them.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

CAZ270-278-NVZ420-423-458-182300-
/O.UPG.KREV.FW.A.0016.210918T2000Z-210919T0300Z/
/O.NEW.KREV.FW.W.0017.210918T2000Z-210919T0300Z/
Surprise Valley California-Eastern Lassen County-
Northern Sierra Front including Carson City, Douglas, Storey,
Southern Washoe, Western Lyon, and Far Southern Lassen Counties-
West Humboldt Basin in Pershing County-Northern Washoe County-
1135 AM PDT Fri Sep 17 2021

...RED FLAG WARNING IN EFFECT FROM 1 PM TO 8 PM PDT SATURDAY FOR
GUSTY WINDS AND LOW HUMIDITY FOR PORTIONS OF NORTHEAST CALIFORNIA
AND WESTERN NEVADA...

The National Weather Service in Reno has issued a Red Flag
Warning for gusty winds and low humidity, which is in effect from
1 PM to 8 PM PDT Saturday. The Fire Weather Watch is no longer in
effect.

* Changes...Upgraded to a Red Flag Warning on Sunday.

* Affected Area...Fire Zone 270 Surprise Valley California, Fire 
  Zone 278 Eastern Lassen County, Fire Zone 420 Northern Sierra 
  Front including Carson City, Douglas, Storey, Southern Washoe, 
  Western Lyon, and Far Southern Lassen Counties, Fire Zone 423 
  West Humboldt Basin in Pershing County and Fire Zone 458 
  Northern Washoe County.

* Winds...Southwest to west 15 to 30 mph with gusts 35 to 45 mph.
  Stronger gusts possible in wind prone areas.

* Humidity...8-15%, except 15-20% closer to the Oregon border.

* Duration...4 to 8 hours.

* Impacts...The combination of gusty winds and low humidity can 
  cause fire to rapidly grow in size and intensity before first 
  responders can contain them.

* Additional Information...Winds will remain elevated Saturday
  night, particularly for wind prone locations, midslopes, and
  ridges.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

CAZ274-NVZ421-182300-
/O.CON.KREV.FW.A.0017.210919T1900Z-210920T0300Z/
Southern Mono County-
Southern Sierra Front including Alpine, Northern Mono, Southern
Lyon, and Western Mineral Counties-
1135 AM PDT Fri Sep 17 2021

...FIRE WEATHER WATCH REMAINS IN EFFECT FROM SUNDAY AFTERNOON
THROUGH SUNDAY EVENING FOR GUSTY WINDS AND LOW HUMIDITY FOR THE
EASTERN SIERRA AND SOUTHERN PORTION OF THE LAHONTAN BASIN...

* Changes...Wind speeds reduced slightly Sunday.

* Affected Area...Fire Zone 274 Southern Mono County, Fire Zone 
  421 Southern Sierra Front including Alpine, Northern Mono, 
  Southern Lyon and and Western Mineral Counties.

* Winds...West 10 to 20 mph with gusts to 35 mph, with stronger 
  gusts possible in wind prone areas.

* Humidity...10-18%, increasing from the north to the south by 
  late afternoon or early evening.

* Duration...3 to 6 hours.

* Impacts...The combination of gusty winds and low humidity can 
  cause fire to rapidly grow in size and intensity before first 
  responders can contain them.

* Additional Information...The greatest concern will be for areas
  near and east of the US-395 corridor. Humidity will be higher
  for the Sierra, but winds will still be gusty.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

http://weather.gov/reno
3 follow-up statements
626 
WWUS85 KREV 181046
RFWREV

URGENT - FIRE WEATHER MESSAGE
National Weather Service Reno NV
346 AM PDT Sat Sep 18 2021

NVZ429-191100-
/O.CON.KREV.FW.W.0017.210918T2000Z-210919T0300Z/
/O.CON.KREV.FW.A.0017.210919T1900Z-210920T0300Z/
Lahontan Basin including Churchill and Eastern Mineral Counties-
346 AM PDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 1 PM THIS AFTERNOON TO
8 PM PDT THIS EVENING FOR GUSTY WINDS AND LOW HUMIDITY FOR THE
LAHONTAN BASIN PRIMARILY NORTH OF US-50...

...FIRE WEATHER WATCH REMAINS IN EFFECT FROM SUNDAY AFTERNOON
THROUGH SUNDAY EVENING FOR GUSTY WINDS AND LOW HUMIDITY PRIMARILY
SOUTH OF US-50...

* Changes...No significant changes.

* Affected Area...Fire Zone 429 Lahontan Basin including 
  Churchill and Eastern Mineral Counties.

* Winds...Southwest to west 15 to 25 mph with gusts to 40 mph
  today, shifting to northwest 10 to 20 mph with gusts to 35 mph
  Sunday afternoon.

* Humidity...Today: 8-13%. Sunday: 12-17%, mainly south of US-50.

* Duration...3 to 7 hours today. 1 to 4 hours Sunday.

* Impacts...The combination of gusty winds and low humidity can 
  cause fire to rapidly grow in size and intensity before first 
  responders can contain them.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

CAZ270-278-NVZ420-423-458-190300-
/O.CON.KREV.FW.W.0017.210918T2000Z-210919T0300Z/
Surprise Valley California-Eastern Lassen County-
Northern Sierra Front including Carson City, Douglas, Storey,
Southern Washoe, Western Lyon, and Far Southern Lassen Counties-
West Humboldt Basin in Pershing County-Northern Washoe County-
346 AM PDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 1 PM THIS AFTERNOON TO
8 PM PDT THIS EVENING FOR GUSTY WINDS AND LOW HUMIDITY FOR
PORTIONS OF NORTHEAST CALIFORNIA AND WESTERN NEVADA...

* Changes...Shorter duration of red flag conditions near Oregon
  border. 

* Affected Area...Fire Zone 270 Surprise Valley California, Fire 
  Zone 278 Eastern Lassen County, Fire Zone 420 Northern Sierra 
  Front including Carson City, Douglas, Storey, Southern Washoe, 
  Western Lyon, and Far Southern Lassen Counties, Fire Zone 423 
  West Humboldt Basin in Pershing County and Fire Zone 458 
  Northern Washoe County.

* Winds...Southwest to west 15 to 30 mph with gusts 35 to 45 
  mph. Stronger gusts possible in wind prone areas.

* Humidity...8-16%, except 15-25% closer to the Oregon border.

* Duration...4 to 8 hours, except 1 to 4 hours closer to the
  Oregon border.

* Impacts...The combination of gusty winds and low humidity can 
  cause fire to rapidly grow in size and intensity before first 
  responders can contain them.

* Additional Information...Winds will remain elevated tonight,  
  particularly for wind prone locations, midslopes, and ridges.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

CAZ274-NVZ421-191100-
/O.CON.KREV.FW.A.0017.210919T1900Z-210920T0300Z/
Southern Mono County-
Southern Sierra Front including Alpine, Northern Mono, Southern
Lyon, and Western Mineral Counties-
346 AM PDT Sat Sep 18 2021

...FIRE WEATHER WATCH REMAINS IN EFFECT FROM SUNDAY AFTERNOON
THROUGH SUNDAY EVENING FOR GUSTY WINDS AND LOW HUMIDITY FOR THE
EASTERN SIERRA AND SOUTHERN PORTION OF THE LAHONTAN BASIN...

* Changes...Shorter duration of possible critical conditions.

* Affected Area...Fire Zone 274 Southern Mono County, Fire Zone 
  421 Southern Sierra Front including Alpine, Northern Mono, 
  Southern Lyon and and Western Mineral Counties.

* Winds...West 10 to 20 mph with gusts to 35 mph, with stronger 
  gusts possible in wind prone areas.

* Humidity...12-18%, mainly east of US-395.

* Duration...1 to 4 hours.

* Impacts...The combination of gusty winds and low humidity can 
  cause fire to rapidly grow in size and intensity before first 
  responders can contain them.

* Additional Information...The greatest concern will be for 
  areas near and east of the US-395 corridor. Humidity will be 
  higher for the Sierra, but winds will still be gusty.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

http://weather.gov/reno
828 
WWUS85 KREV 181738
RFWREV

URGENT - FIRE WEATHER MESSAGE
National Weather Service Reno NV
1038 AM PDT Sat Sep 18 2021

NVZ429-190300-
/O.CAN.KREV.FW.A.0017.210919T1900Z-210920T0300Z/
/O.CON.KREV.FW.W.0017.210918T2000Z-210919T0300Z/
Lahontan Basin including Churchill and Eastern Mineral Counties-
1038 AM PDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM PDT THIS EVENING
FOR GUSTY WINDS AND LOW HUMIDITY FOR THE LAHONTAN BASIN... 

...FIRE WEATHER WATCH IS CANCELLED FOR GUSTY WINDS AND LOW 
HUMIDITY PRIMARILY SOUTH OF US-50...

The National Weather Service in Reno has cancelled the Fire
Weather Watch.

* Changes...The Fire Weather Watch is being cancelled for Sunday
  due to a shorter duration and less widespread area of
  anticipated critical conditions.

* Affected Area...Fire Zone 429 Lahontan Basin including 
  Churchill and Eastern Mineral Counties.

* Winds...Southwest to west 15 to 25 mph with gusts to 40 mph 
  today, shifting to northwest 10 to 20 mph with gusts to 35 mph 
  Sunday afternoon.

* Humidity...Today: 8-13%. Sunday: 12-20%, lowest south of US-50.

* Duration...3 to 7 hours today. Localized for a couple hours 
  Sunday.

* Impacts...The combination of gusty winds and low humidity can 
  cause fire to rapidly grow in size and intensity before first 
  responders can contain them.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

NVZ421-190300-
/O.CAN.KREV.FW.A.0017.210919T1900Z-210920T0300Z/
/O.EXA.KREV.FW.W.0017.210918T2000Z-210919T0300Z/
Southern Sierra Front including Alpine, Northern Mono, Southern
Lyon, and Western Mineral Counties-
1038 AM PDT Sat Sep 18 2021

...RED FLAG WARNING IN EFFECT UNTIL 8 PM PDT THIS EVENING FOR
GUSTY WINDS AND LOW HUMIDITY FOR THE EASTERN PORTION OF THE SOUTHERN
SIERRA FRONT...

 ...FIRE WEATHER WATCH IS CANCELLED FOR GUSTY WINDS AND LOW 
HUMIDITY FOR THE SOUTHERN SIERRA FRONT ON SUNDAY...

The National Weather Service in Reno has issued a Red Flag
Warning for gusty winds and low humidity, which is in effect
until 8 PM PDT this evening. The Fire Weather Watch has been
cancelled.

* Changes...Added the zone to the Red Flag Warning today. The 
  Fire Weather Watch is being cancelled for Sunday due to a 
  shorter duration and less widespread area of anticipated 
  critical conditions.

* Affected Area...Fire Zone 421 Southern Sierra Front including 
  Alpine, Northern Mono, Southern Lyon and and Western Mineral 
  Counties.

* Winds...Today: Southwest 15-20 mph with gusts 35 to 40 mph.

* Humidity...Today: 8-18%, lowest east of US-395.

* Duration...3 to 7 hours.

* Impacts...The combination of gusty winds and low humidity can 
  cause fire to rapidly grow in size and intensity before first 
  responders can contain them.

* Additional Information...The greatest concern will be for 
  areas near and east of the US-395 corridor. Humidity will be 
  higher for the Sierra, but winds will still be gusty.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

CAZ274-181845-
/O.CAN.KREV.FW.A.0017.210919T1900Z-210920T0300Z/
Southern Mono County-
1038 AM PDT Sat Sep 18 2021

...FIRE WEATHER WATCH IS CANCELLED FOR GUSTY WINDS AND LOW
HUMIDITY FOR THE EASTERN SIERRA...

The National Weather Service in Reno has cancelled the Fire
Weather Watch.

The Fire Weather Watch is being cancelled Sunday due to a shorter
duration and less widespread area of anticipated critical 
conditions. Winds will be rather breezy, but won't overlap for a 
long enough duration with lower humidity.

$$

CAZ270-278-NVZ420-423-458-190300-
/O.CON.KREV.FW.W.0017.210918T2000Z-210919T0300Z/
Surprise Valley California-Eastern Lassen County-
Northern Sierra Front including Carson City, Douglas, Storey,
Southern Washoe, Western Lyon, and Far Southern Lassen Counties-
West Humboldt Basin in Pershing County-Northern Washoe County-
1038 AM PDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 8 PM PDT THIS EVENING
FOR GUSTY WINDS AND LOW HUMIDITY FOR PORTIONS OF NORTHEAST
CALIFORNIA AND WESTERN NEVADA...

* Changes...None.

* Affected Area...Fire Zone 270 Surprise Valley California, Fire 
  Zone 278 Eastern Lassen County, Fire Zone 420 Northern Sierra 
  Front including Carson City, Douglas, Storey, Southern Washoe, 
  Western Lyon, and Far Southern Lassen Counties, Fire Zone 423 
  West Humboldt Basin in Pershing County and Fire Zone 458 
  Northern Washoe County.

* Winds...Southwest to west 15 to 30 mph with gusts 35 to 45 
  mph. Stronger gusts possible in wind prone areas.

* Humidity...8-16%, except 10-20% closer to the Oregon border.

* Duration...3 to 8 hours.

* Impacts...The combination of gusty winds and low humidity can 
  cause fire to rapidly grow in size and intensity before first 
  responders can contain them.

* Additional Information...Winds will remain elevated tonight, 
  particularly for wind prone locations, midslopes, and ridges.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Avoid outdoor activities that can cause a spark near dry
vegetation, such as yard work, target shooting, or campfires.
Follow local fire restrictions. Check weather.gov/reno for
updates and livingwithfire.info for preparedness tips.

&&

$$

http://weather.gov/reno
707 
WWUS85 KREV 190255
RFWREV

URGENT - FIRE WEATHER MESSAGE
National Weather Service Reno NV
755 PM PDT Sat Sep 18 2021

CAZ270-278-NVZ420-421-423-429-458-190400-
/O.EXP.KREV.FW.W.0017.000000T0000Z-210919T0300Z/
Surprise Valley California-Eastern Lassen County-
Northern Sierra Front including Carson City, Douglas, Storey,
Southern Washoe, Western Lyon, and Far Southern Lassen Counties-
Southern Sierra Front including Alpine, Northern Mono, Southern
Lyon, and Western Mineral Counties-
West Humboldt Basin in Pershing County-
Lahontan Basin including Churchill and Eastern Mineral Counties-
Northern Washoe County-
755 PM PDT Sat Sep 18 2021

...RED FLAG WARNINGS WILL EXPIRE AT 8 PM PDT THIS EVENING FOR
GUSTY WINDS AND LOW HUMIDITY...

With rising humidities and decreasing valley winds all Red Flag 
Warnings will be expire at 8 pm. However, wind prone and mid- 
slope locations north of US-50, and mountain ridges will remain 
gusty all night long, with midslopes and ridges potentially seeing
the strongest winds of this event overnight into the early Sunday
morning hours. Periodic stronger gusts may surface in lower 
elevations overnight, possibly becoming more steady just before 
daybreak.

$$

http://weather.gov/reno

The office that day

Everything else NWS Reno, NV issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 17, 11:38 AM PDTLake Wind AdvisoryREVChurchill, Douglas, Lyon, Pershing, Washoe32 hr

Nearby

Red Flag Warnings in Nevada, 2021Red Flag Warnings in California, 2021Every red flag warning in 2021

Sources

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