Alert archive / Idaho / Red Flag Warnings in 2021

Red Flag Warning 16, NWS Boise, ID

September 16, 202111 counties in Idaho

NWS Boise, ID issued this red flag warning at Sep 16, 2021, 1:24 PM MDT for 11 counties in Idaho. It took effect at Sep 17, 2021, 1:00 PM MDT. It was in force for 32 hr. 30 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Sep 16, 2021, 1:24 PM MDT (19:24 UTC)
In effect from
Sep 17, 2021, 1:00 PM MDT
Expired
Sep 18, 2021, 9:00 PM MDT
In force
32 hr
Issued by
NWS Boise, ID

Counties Boise County, ID, Camas County, ID, Elmore County, ID, Gem County, ID, Gooding County, ID, Idaho County, ID, Jerome County, ID, Lincoln County, ID, Owyhee County, ID, Twin Falls County, ID, Valley County, ID

The radar

The Boise radar (KCBX), 82 km from the middle of the area, began a volume at 19:25 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.

What was reported inside it

TimeReportWhereRemark
Sep 18, 12:45 PM MDTNON-TSTM WND GST 4214 Ese Hollister, IDMESONET STATION TGFI1 TRAIL GULCH.
Sep 18, 1:42 PM MDTNON-TSTM WND GST 4719 Ese Riddle, IDMESONET STATION PCKI1 POLE CREEK.
Sep 18, 2:00 PM MDTNON-TSTM WND GST 5710 Nw Soldier, IDMESONET STATION SLDMT 9.8 NW SOLDIER (UUNET).
Sep 18, 2:31 PM MDTNON-TSTM WND GST 4413 Ssw Riddle, IDMESONET STATION SPAI1 SHO-PAI.
Sep 18, 2:33 PM MDTNON-TSTM WND GST 401 S Mccall, IDASOS STATION KMYL MCCALL.
Sep 18, 2:52 PM MDTNON-TSTM WND GST 4415 E Mackay Bar, IDLODGEPOLE RAWS.
Sep 18, 2:55 PM MDTNON-TSTM WND GST 4615 Sse Silver City, IDMESONET STATION TRII1 TRIANGLE.
Sep 18, 3:00 PM MDTNON-TSTM WND GST 5114 E Atlanta, IDMESONET STATION VINMT 14.5 S OBSIDIAN (UUNET).
Sep 18, 3:39 PM MDTNON-TSTM WND GST 4417 Se Atlanta, IDMESONET STATION FLEI1 FLECK SUMMIT.
Sep 18, 3:55 PM MDTNON-TSTM WND GST 4132 Wnw Riddle, IDMESONET STATION BFRI1 BRACE FLAT.
Sep 18, 3:55 PM MDTNON-TSTM WND GST 4317 Wsw Hagerman, IDMESONET STATION TWBI1 TWIN BUTTES.
Sep 18, 4:08 PM MDTNON-TSTM WND GST 414 Ssw Horseshoe Bend, IDMESONET STATION EW2058 HORSESHOE BEND.
Sep 18, 4:18 PM MDTNON-TSTM WND GST 414 Ssw Horseshoe Bend, IDMESONET STATION EW2058 HORSESHOE BEND.
Sep 18, 4:31 PM MDTNON-TSTM WND GST 4513 Ssw Riddle, IDMESONET STATION SPAI1 SHO-PAI.
Sep 18, 4:45 PM MDTNON-TSTM WND GST 4914 Ese Hollister, IDMESONET STATION TGFI1 TRAIL GULCH.
Sep 18, 4:49 PM MDTNON-TSTM WND GST 4916 Nw Mountain Home, IDMESONET STATION UP237 16.0 N MOUNTAIN HOME AFB (UPR).
Sep 18, 4:52 PM MDTNON-TSTM WND GST 4220 Wsw Castleford, IDMESONET STATION HBFI1 HORSE BUTTE.
Sep 18, 5:00 PM MDTNON-TSTM WND GST 415 Sse Grand View, IDMESONET STATION GDVI 5.2 SE GRAND VIEW (AGRIMET).
Sep 18, 5:05 PM MDTNON-TSTM WND GST 551 S Mountain Home Afb, IDAWOS STATION KMUO MOUNTAIN HOME AFB.
Sep 18, 5:25 PM MDTNON-TSTM WND GST 548 Wnw Mountain Home Afb, IDMESONET STATION TS962 7 WNW MOUNTAIN HOME AFB.
Sep 18, 5:31 PM MDTNON-TSTM WND GST 4713 Ssw Riddle, IDMESONET STATION SPAI1 SHO-PAI.
Sep 18, 5:44 PM MDTNON-TSTM WND GST 4110 Ssw Hill City, IDMESONET STATION DEHI1 DEER HAVEN.
Sep 18, 5:52 PM MDTNON-TSTM WND GST 4320 Wsw Castleford, IDMESONET STATION HBFI1 HORSE BUTTE.
Sep 18, 5:55 PM MDTNON-TSTM WND GST 5317 Wsw Hagerman, IDMESONET STATION TWBI1 TWIN BUTTES.
Sep 18, 6:00 PM MDTNON-TSTM WND GST 437 Ssw Glenns Ferry, IDMESONET STATION GFRI 6.7 SW GLENNS FERRY (AGRIMET).
Sep 18, 6:02 PM MDTNON-TSTM WND GST 427 Se Hot Springs, IDMESONET STATION TT087 SAYLOR CREEK.
Sep 18, 6:05 PM MDTNON-TSTM WND GST 412 W Mountain Home, IDAWOS STATION KU76 1 W MOUNTAIN HOME.
Sep 18, 6:15 PM MDTNON-TSTM WND GST 505 Sse Mountain Home, IDMESONET STATION UP078 4.6 SE MOUNTAIN HOME (UPR).
Sep 18, 6:52 PM MDTNON-TSTM WND GST 521 S Mountain Home Afb, IDMESONET STATION MTHI1 MOUNTAIN HOME AFB RAWS.
Sep 18, 6:55 PM MDTNON-TSTM WND GST 586 S Twin Falls, IDASOS STATION KTWF TWIN FALLS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Boise Airport, ID (KBOI), launched 12:00Z, 7.4 hours before the alert went out and 79 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, Boise Airport, ID at 12:00Z on 2021-09-16Temperature 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, Boise Airport, ID at 12:00Z on 2021-09-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -168 square meters per square second.1939587897117Sfc1 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
2777 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
-168 m²/s²
0-3 km storm-relative helicity
-80 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

560 
WWUS85 KBOI 161924
RFWBOI

URGENT - FIRE WEATHER MESSAGE
National Weather Service Boise ID
124 PM MDT Thu Sep 16 2021

...RED FLAG WARNING ISSUED FOR STRONG WINDS AND LOW RH...

.Strong winds and low relative humidity ahead of an upper level 
system and accompanying cold front will produce dangerous fire 
weather conditions Friday afternoon through Saturday evening. The 
mountains of central Idaho will be the first to see the effects, 
with winds increasing Friday afternoon. Due to poor recovery RH 
overnight, we are extending the warning in the mountains through 
the overnight hours all the way into Saturday evening. In the 
lower elevation districts in Idaho, and in southeast Oregon, the 
warning starts Saturday afternoon and extends into Saturday 
evening. This event will be followed by wetting rains behind the 
cold front, with rain starting in eastern Oregon Saturday evening 
and moving east through the weekend, ending in southwest Idaho 
Monday.

IDZ402-403-421-171500-
/O.NEW.KBOI.FW.W.0016.210917T1900Z-210919T0300Z/
Eastern Payette National Forest-Northern Boise National Forest-
Southern Boise National Forest/Western Sawtooth National Forest-
124 PM MDT Thu Sep 16 2021

...RED FLAG WARNING IN EFFECT FROM 1 PM FRIDAY TO 9 PM MDT
SATURDAY FOR GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR EASTERN
PAYETTE NATIONAL FOREST...NORTHERN BOISE NATIONAL FOREST AND
SOUTHERN BOISE NATIONAL FOREST/WESTERN SAWTOOTH NATIONAL FOREST...
WHICH ARE FIRE WEATHER ZONES 402...403 AND 421...

The National Weather Service in Boise has issued a Red Flag
Warning, which is in effect from 1 PM Friday to 9 PM MDT
Saturday. 

* WINDS...Gusts to 30 mph Friday and 40 mph Saturday.

* RELATIVE HUMIDITY...10 to 15 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will occur shortly.

&&

$$

IDZ423-424-426-ORZ636-637-171500-
/O.NEW.KBOI.FW.W.0016.210918T1900Z-210919T0300Z/
Owyhee Mountains-Western Twin Falls BLM-Southern Highlands-
Burns BLM-Vale BLM-
124 PM MDT Thu Sep 16 2021 /1224 PM PDT Thu Sep 16 2021/

...RED FLAG WARNING IN EFFECT FROM 1 PM MDT /NOON PDT/ TO 9 PM
MDT /8 PM PDT/ SATURDAY FOR GUSTY WINDS AND LOW RELATIVE
HUMIDITIES FOR OWYHEE MOUNTAINS...WESTERN TWIN FALLS BLM...
SOUTHERN HIGHLANDS...BURNS BLM AND VALE BLM...WHICH ARE FIRE
WEATHER ZONES 423...424...426...636 AND 637...

The National Weather Service in Boise has issued a Red Flag
Warning, which is in effect from 1 PM MDT /noon PDT/ to 9 PM MDT
/8 PM PDT/ Saturday. 

* WINDS...Gusts 30 to 40 mph.

* RELATIVE HUMIDITY...8 to 15 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will occur shortly.

&&

$$


W
5 follow-up statements
081 
WWUS85 KBOI 171436
RFWBOI

URGENT - FIRE WEATHER MESSAGE
National Weather Service Boise ID
836 AM MDT Fri Sep 17 2021

...RED FLAG WARNING FOR GUSTY WINDS AND LOW RELATIVE 
HUMIDITIES...

.Gusty winds and low relative humidities ahead of an upper level 
system and accompanying cold front will produce dangerous fire 
weather conditions this afternoon through Saturday evening. 

IDZ402-403-421-181500-
/O.CON.KBOI.FW.W.0016.210917T1900Z-210919T0300Z/
Eastern Payette National Forest-Northern Boise National Forest-
Southern Boise National Forest/Western Sawtooth National Forest-
836 AM MDT Fri Sep 17 2021

...RED FLAG WARNING REMAINS IN EFFECT FROM 1 PM THIS AFTERNOON TO
9 PM MDT SATURDAY FOR GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR
EASTERN PAYETTE NATIONAL FOREST...NORTHERN BOISE NATIONAL FOREST
AND SOUTHERN BOISE NATIONAL FOREST/WESTERN SAWTOOTH NATIONAL
FOREST... WHICH ARE FIRE WEATHER ZONES 402...403 AND 421...

* WINDS...Gusts to 30 mph today and 40 mph Saturday.

* RELATIVE HUMIDITY...10 to 15 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will occur shortly.

&&

$$

IDZ423-424-426-ORZ636-637-181500-
/O.CON.KBOI.FW.W.0016.210918T1900Z-210919T0300Z/
Owyhee Mountains-Western Twin Falls BLM-Southern Highlands-
Burns BLM-Vale BLM-
836 AM MDT Fri Sep 17 2021 /736 AM PDT Fri Sep 17 2021/

...RED FLAG WARNING REMAINS IN EFFECT FROM 1 PM MDT /NOON PDT/ TO
9 PM MDT /8 PM PDT/ SATURDAY FOR GUSTY WINDS AND LOW RELATIVE
HUMIDITIES FOR OWYHEE MOUNTAINS...WESTERN TWIN FALLS BLM...
SOUTHERN HIGHLANDS...BURNS BLM AND VALE BLM...WHICH ARE FIRE
WEATHER ZONES 423...424...426...636 AND 637...

* WINDS...Gusts 30 to 40 mph.

* RELATIVE HUMIDITY...8 to 15 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will occur shortly.

&&

$$


W
214 
WWUS85 KBOI 181410
RFWBOI

URGENT - FIRE WEATHER MESSAGE
National Weather Service Boise ID
810 AM MDT Sat Sep 18 2021

...RED FLAG WARNING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITIES...

.Gusty winds and low relative humidities ahead of an upper level 
system and accompanying cold front will produce dangerous fire 
weather conditions through this evening. The front will enter eastern
Oregon early this afternoon, move into the mountain districts of 
Idaho from late this afternoon into this evening, and move into the 
remainder of southwest Idaho this evening. Rain will follow these 
winds from this evening through Sunday with wetting rains likely in 
most areas.

IDZ402-403-421-182215-
/O.CON.KBOI.FW.W.0016.000000T0000Z-210919T0300Z/
Eastern Payette National Forest-Northern Boise National Forest-
Southern Boise National Forest/Western Sawtooth National Forest-
810 AM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR EASTERN PAYETTE
NATIONAL FOREST...NORTHERN BOISE NATIONAL FOREST AND SOUTHERN
BOISE NATIONAL FOREST/WESTERN SAWTOOTH NATIONAL FOREST... WHICH
ARE FIRE WEATHER ZONES 402...403 AND 421...

* WINDS...Gusts to 30 mph today and 40 mph Saturday.

* RELATIVE HUMIDITY...10 to 20 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will occur shortly.

&&

$$

IDZ423-424-426-ORZ636-637-182215-
/O.CON.KBOI.FW.W.0016.210918T1900Z-210919T0300Z/
Owyhee Mountains-Western Twin Falls BLM-Southern Highlands-
Burns BLM-Vale BLM-
810 AM MDT Sat Sep 18 2021 /710 AM PDT Sat Sep 18 2021/

...RED FLAG WARNING REMAINS IN EFFECT FROM 1 PM MDT /NOON PDT/
THIS AFTERNOON TO 9 PM MDT /8 PM PDT/ THIS EVENING FOR GUSTY
WINDS AND LOW RELATIVE HUMIDITIES FOR OWYHEE MOUNTAINS...WESTERN
TWIN FALLS BLM... SOUTHERN HIGHLANDS...BURNS BLM AND VALE BLM...
WHICH ARE FIRE WEATHER ZONES 423...424...426...636 AND 637...

* WINDS...Gusts 30 to 40 mph.

* RELATIVE HUMIDITY...9 to 15 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will occur shortly.

&&

$$


W
802 
WWUS85 KBOI 181856
RFWBOI

URGENT - FIRE WEATHER MESSAGE
National Weather Service Boise ID
1256 PM MDT Sat Sep 18 2021

...RED FLAG WARNING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITIES...

.Gusty winds and low relative humidities ahead of an upper level
system and accompanying cold front will produce dangerous fire
weather conditions through this evening. The front will enter
eastern Oregon early this afternoon, move into the mountain
districts of Idaho from late this afternoon into this evening,
and move into the remainder of southwest Idaho this evening. Rain
will follow these winds from this evening through Sunday with
wetting rains likely in most areas.

IDZ423-424-426-ORZ636-637-190300-
/O.CON.KBOI.FW.W.0016.210918T1900Z-210919T0300Z/
Owyhee Mountains-Western Twin Falls BLM-Southern Highlands-
Burns BLM-Vale BLM-
1256 PM MDT Sat Sep 18 2021 /1156 AM PDT Sat Sep 18 2021/

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT /8 PM PDT/
THIS EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR
OWYHEE MOUNTAINS...WESTERN TWIN FALLS BLM...SOUTHERN HIGHLANDS...
BURNS BLM AND VALE BLM...WHICH ARE FIRE WEATHER ZONES 423...424...
426...636 AND 637...

* WINDS...Gusts 30 to 40 mph.

* RELATIVE HUMIDITY...7 to 15 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will occur shortly.

&&

$$

IDZ402-403-421-190300-
/O.CON.KBOI.FW.W.0016.000000T0000Z-210919T0300Z/
Eastern Payette National Forest-Northern Boise National Forest-
Southern Boise National Forest/Western Sawtooth National Forest-
1256 PM MDT Sat Sep 18 2021

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT THIS EVENING
FOR GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR EASTERN PAYETTE
NATIONAL FOREST...NORTHERN BOISE NATIONAL FOREST AND SOUTHERN
BOISE NATIONAL FOREST/WESTERN SAWTOOTH NATIONAL FOREST...WHICH
ARE FIRE WEATHER ZONES 402...403 AND 421...

* WINDS...Gusts 30 to 50 mph.

* RELATIVE HUMIDITY...10 to 20 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will occur shortly.

&&

$$


W
828 
WWUS85 KBOI 182041
RFWBOI

URGENT - FIRE WEATHER MESSAGE
National Weather Service Boise ID
241 PM MDT Sat Sep 18 2021

...RED FLAG WARNING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITIES...

.Gusty winds and low relative humidities ahead of an upper level
system and accompanying cold front will produce dangerous fire
weather conditions through this evening. The front has entered 
eastern Oregon, and will move into the mountain districts of 
Idaho from late this afternoon into this evening, and move into 
the remainder of southwest Idaho this evening. Rain will follow 
the cold front and last through Sunday, with wetting rains likely
in most areas.

ORZ636-182145-
/O.CAN.KBOI.FW.W.0016.000000T0000Z-210919T0300Z/
Burns BLM-
141 PM PDT Sat Sep 18 2021

...RED FLAG WARNING IS CANCELLED FOR GUSTY WINDS AND LOW RELATIVE
HUMIDITIES FOR OWYHEE MOUNTAINS...WESTERN TWIN FALLS BLM...
SOUTHERN HIGHLANDS... BURNS BLM AND VALE BLM...WHICH ARE FIRE
WEATHER ZONES 423...424... 426...636 AND 637...

The National Weather Service in Boise has cancelled the Red Flag
Warning. 

Rain showers have moved into most of the Burns BLM, raising the
RH well above Red Flag criteria. Therefore, the warning has been
cancelled.

$$

IDZ402-403-421-423-424-426-ORZ637-190300-
/O.CON.KBOI.FW.W.0016.000000T0000Z-210919T0300Z/
Eastern Payette National Forest-Northern Boise National Forest-
Southern Boise National Forest/Western Sawtooth National Forest-
Owyhee Mountains-Western Twin Falls BLM-Southern Highlands-
Vale BLM-
241 PM MDT Sat Sep 18 2021 /141 PM PDT Sat Sep 18 2021/

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 9 PM MDT /8 PM PDT/
THIS EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR
OWYHEE MOUNTAINS...WESTERN TWIN FALLS BLM...SOUTHERN HIGHLANDS...
BURNS BLM AND VALE BLM...WHICH ARE FIRE WEATHER ZONES 423...424...
 426...636 AND 637...

* WINDS...Gusts 30 to 50 mph.

* RELATIVE HUMIDITY...8 to 20 percent.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will occur shortly.

&&

$$


W
369 
WWUS85 KBOI 190256
RFWBOI

URGENT - FIRE WEATHER MESSAGE
National Weather Service Boise ID
856 PM MDT Sat Sep 18 2021

...RED FLAG WILL EXPIRE AT 9 PM MDT...

IDZ402-403-421-423-424-426-ORZ637-190400-
/O.EXP.KBOI.FW.W.0016.000000T0000Z-210919T0300Z/
Eastern Payette National Forest-Northern Boise National Forest-
Southern Boise National Forest/Western Sawtooth National Forest-
Owyhee Mountains-Western Twin Falls BLM-Southern Highlands-
Vale BLM-
856 PM MDT Sat Sep 18 2021 /756 PM PDT Sat Sep 18 2021/

...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT /8 PM PDT/ THIS
EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITIES FOR OWYHEE
MOUNTAINS...WESTERN TWIN FALLS BLM...SOUTHERN HIGHLANDS... BURNS
BLM AND VALE BLM...WHICH ARE FIRE WEATHER ZONES 423...424... 
426...636 AND 637...

Winds across the area have weakened this evening and will continue
to do so overnight. Additionally, relative humidity levels have
rebounded to above critical values. Therefore, the warning will be
allowed to expire at 9 PM MDT.

$$


W

Nearby

Red Flag Warnings in Idaho, 2021Red Flag Warnings in Oregon, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.