Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 84, NWS Flagstaff, AZ

July 22, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 22, 2021, 4:04 PM MST for Coconino County, Arizona. It was in force for 116 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jul 22, 2021, 4:04 PM MST (23:04 UTC)
Expired
Jul 22, 2021, 6:00 PM MST
In force
116 min
Issued by
NWS Flagstaff, AZ
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Coconino County, AZ

The radar

The Cedar City radar (KICX), 150 km from the middle of the area, began a volume at 23:04 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

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 11.1 hours before the alert went out and 189 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, Flgstf/Belemont, AZ at 12:00Z on 2021-07-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 196 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 2021-07-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 square meters per square second.1939Sfc1 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
196 J/kg
Mixed-layer CIN
-125 J/kg
Mixed-layer LCL
1415 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
54 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

288 
WGUS55 KFGZ 222304
FFWFGZ
AZC005-230100-
/O.NEW.KFGZ.FF.W.0084.210722T2304Z-210723T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
404 PM MST Thu Jul 22 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  The Antelope Creek basin in...
  Coconino County in north central Arizona...

* Until 600 PM MST.

* At 403 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain over the Antelope Creek basin. Between 0.5 and 1.5 
  inches of rain have fallen. Flash flooding is ongoing or expected 
  to begin shortly.

  HAZARD...Life-threatening flash flooding. Thunderstorms
           producing flash flooding in and around the Antelope
           Creek basin.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of areas in and around
           the Antelope Creek basin.

* Some locations that will experience flash flooding include...
  Antelope Canyon Near Sr 98, Antelope Creek Basin, Glen Canyon 
  National Recreation Area.

This includes the following slot canyons...
Upper Antelope Canyon, Lower Antelope Canyon, Owl Canyon, 
Rattlesnake Canyon and Ramshead Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get out of Antelope Canyon and other area slot canyons immediately! 
Deadly flash flooding is imminent or occurring!

&&

LAT...LON 3694 11143 3690 11138 3683 11133 3683 11139
      3689 11143 3694 11144

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

McCollum
2 follow-up statements
236 
WGUS75 KFGZ 222352
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
452 PM MST Thu Jul 22 2021

AZC005-230100-
/O.CON.KFGZ.FF.W.0084.000000T0000Z-210723T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
452 PM MST Thu Jul 22 2021

...FLASH FLOOD WARNING FOR THE ANTELOPE CREEK BASIN REMAINS IN 
EFFECT UNTIL 6 PM MST THIS EVENING FOR COCONINO COUNTY...

At 451 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain earlier over the Antelope Creek basin have dissipated. Between 
0.5 and 1.5 inches of rain have fallen. Flash flooding is ongoing or 
expected to begin shortly.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding in and around the Antelope Creek basin.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of areas in and around
         the Antelope Creek basin.

Some locations that will experience flash flooding include...
  Page, Antelope Canyon Near Sr 98, Antelope Creek Basin.

This includes the following slot canyons...
Upper Antelope Canyon, Lower Antelope Canyon, Owl Canyon, 
Rattlesnake Canyon and Ramshead Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get out of Antelope Canyon and other area slot canyons immediately! 
Deadly flash flooding is imminent or occurring!

&&

LAT...LON 3694 11143 3690 11138 3683 11133 3683 11139
      3689 11143 3694 11144

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

McCollum
382 
WGUS75 KFGZ 230052
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
552 PM MST Thu Jul 22 2021

AZC005-230102-
/O.EXP.KFGZ.FF.W.0084.000000T0000Z-210723T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
552 PM MST Thu Jul 22 2021

...FLASH FLOOD WARNING FOR THE ANTELOPE CREEK BASIN WILL EXPIRE AT 6 
PM MST THIS EVENING FOR COCONINO COUNTY...

Flood waters have receded and heavy rain has ended. Flooding is no 
longer expected to pose a threat along the Antelope Creek drainage.

LAT...LON 3694 11143 3690 11138 3683 11133 3683 11139
      3689 11143 3694 11144

$$

McCollum

The office that day

Everything else NWS Flagstaff, AZ issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 21, 6:38 PM MSTFlash Flood Warning Considerable damage threatFGZGila3 hr
Jul 21, 6:53 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino112 min
Jul 22, 12:28 PM MSTAreal Flood AdvisoryFGZCoconino3 hr
Jul 22, 2:10 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino3 hr
Jul 22, 3:01 PM MSTSevere Thunderstorm WarningFGZCoconino44 min
Jul 22, 3:31 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino115 min
Jul 22, 3:58 PM MSTFlash Flood Warning Considerable damage threatFGZNavajo3 hr

Nearby

Flash Flood Warnings in Arizona, 2021Every flash flood 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.