Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 227, NWS Flagstaff, AZ

September 2, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Sep 2, 2021, 5:27 PM MST for Coconino County, Arizona. It was in force for 5 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 2, 2021, 5:27 PM MST (00:27 UTC)
Expired
Sep 2, 2021, 10:30 PM MST
In force
5 hr
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), 155 km from the middle of the area, began a volume at 00:27 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 00:00Z, 0.5 hours before the alert went out and 182 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 00:00Z on 2021-09-03Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 107 joules per kilogram.LCLEL10008507005003002001001 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 00:00Z on 2021-09-03The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 7 square meters per square second.19395878Sfc1 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
107 J/kg
Mixed-layer CIN
-6 J/kg
Mixed-layer LCL
1467 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
7 m²/s²
0-3 km storm-relative helicity
-36 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

113 
WGUS55 KFGZ 030027
FFWFGZ
AZC005-030330-
/O.NEW.KFGZ.FF.W.0227.210903T0027Z-210903T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
527 PM MST Thu Sep 2 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 830 PM MST.

* At 526 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain over the Antelope Creek basin. Between 0.5 and 1 inch 
  of rain has 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 Creek Basin, Antelope Canyon Near Sr 98, Glen Canyon 
  National Recreation Area, Antelope Canyon, Lake Powell and Navajo 
  Reservation.

This includes the following slot canyons...
Upper Antelope Canyon, Lower Antelope Canyon, Canyon X, Cardiac 
Canyon, Owl Canyon, Rattlesnake Canyon, Mountain Sheep Canyon, 
Ramshead Canyon, Wind Pebble Canyon and Porcupine Canyon.

This includes the following creeks, washes and rivers...
  Antelope Creek, Sand Wash and Peach Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3695 11143 3694 11142 3692 11135 3662 11124
      3659 11141 3669 11143 3689 11143 3694 11144

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

$$

MCT
4 follow-up statements
230 
WGUS75 KFGZ 030124
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
624 PM MST Thu Sep 2 2021

AZC005-030330-
/O.CON.KFGZ.FF.W.0227.000000T0000Z-210903T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
624 PM MST Thu Sep 2 2021

...FLASH FLOOD WARNING FOR THE ANTELOPE CREEK BASIN REMAINS IN 
EFFECT UNTIL 830 PM MST THIS EVENING FOR COCONINO COUNTY...

At 623 PM MST, Doppler radar indicated heavy rain has ended with 
light rain continuing at this time over the Antelope Creek basin. 
Between 0.5 and 1 inch of rain fell earlier and runoff will lead to 
flash flooding downstream along Antelope Creek and Antelope Canyon.

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 Creek Basin, Antelope Canyon Near Sr 98, Glen Canyon 
  National Recreation Area, Antelope Canyon, Lake Powell and Navajo 
  Reservation.

This includes the following slot canyons...
Upper Antelope Canyon, Lower Antelope Canyon, Canyon X, Cardiac 
Canyon, Owl Canyon, Rattlesnake Canyon, Mountain Sheep Canyon, 
Ramshead Canyon, Wind Pebble Canyon and Porcupine Canyon.

This includes the following creeks, washes and rivers...
  Antelope Creek, Sand Wash and Peach Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3695 11143 3694 11142 3692 11135 3662 11124
      3659 11141 3669 11143 3689 11143 3694 11144

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

$$

MCT
162 
WGUS55 KFGZ 030325
FFWFGZ
AZC005-030530-
/O.EXT.KFGZ.FF.W.0227.000000T0000Z-210903T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
825 PM MST Thu Sep 2 2021

The National Weather Service in Flagstaff has extended the

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

* Until 1030 PM MST.

* At 824 PM MST, Doppler radar indicated additional thunderstorms 
  producing heavy rain over the Antelope Creek basin. Between 0.5 
  and 1 inch of rain has already fallen. Additional rainfall amounts 
  of 0.25 to 0.75 inches are possible in the warned area. 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 Creek Basin, Antelope Canyon Near Sr 98, Glen Canyon 
  National Recreation Area, Antelope Canyon, Lake Powell and Navajo 
  Reservation.

This includes the following slot canyons...
Upper Antelope Canyon, Lower Antelope Canyon, Canyon X, Cardiac 
Canyon, Owl Canyon, Rattlesnake Canyon, Mountain Sheep Canyon, 
Ramshead Canyon, Wind Pebble Canyon and Porcupine Canyon.

This includes the following creeks, washes and rivers...
  Antelope Creek, Sand Wash and Peach Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3695 11143 3694 11142 3692 11135 3662 11124
      3659 11141 3669 11143 3689 11143 3694 11144

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

$$

MCT
596 
WGUS75 KFGZ 030424
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
924 PM MST Thu Sep 2 2021

AZC005-030530-
/O.CON.KFGZ.FF.W.0227.000000T0000Z-210903T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
924 PM MST Thu Sep 2 2021

...FLASH FLOOD WARNING FOR THE ANTELOPE CREEK BASIN REMAINS IN 
EFFECT UNTIL 1030 PM MST THIS EVENING FOR COCONINO COUNTY...

At 923 PM MST, Doppler radar indicated light rain continues over the 
Antelope Creek basin at this time. Between 0.5 and 1 inch of rain 
has fallen. Additional rainfall amounts of 0.1 to 0.25 inches are 
possible in the warned area. Flash flooding is ongoing or expected 
to begin shortly.

HAZARD...Life-threatening flash flooding. Heavy rain 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 Creek Basin, Antelope Canyon Near Sr 98, Glen Canyon 
  National Recreation Area, Antelope Canyon, Lake Powell and Navajo 
  Reservation.

This includes the following slot canyons...
Upper Antelope Canyon, Lower Antelope Canyon, Canyon X, Cardiac 
Canyon, Owl Canyon, Rattlesnake Canyon, Mountain Sheep Canyon, 
Ramshead Canyon, Wind Pebble Canyon and Porcupine Canyon.

This includes the following creeks, washes and rivers...
  Antelope Creek, Sand Wash and Peach Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3695 11143 3694 11142 3692 11135 3662 11124
      3659 11141 3669 11143 3689 11143 3694 11144

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

$$

MCT
864 
WGUS75 KFGZ 030521
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
1021 PM MST Thu Sep 2 2021

AZC005-030531-
/O.EXP.KFGZ.FF.W.0227.000000T0000Z-210903T0530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
1021 PM MST Thu Sep 2 2021

...FLASH FLOOD WARNING FOR THE ANTELOPE CREEK BASIN WILL EXPIRE AT 
1030 PM MST THIS EVENING FOR COCONINO COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to use caution near the Antelope Creek 
drainage which will likely see elevated water levels tonight.

LAT...LON 3695 11143 3694 11142 3692 11135 3662 11124
      3659 11141 3669 11143 3689 11143 3694 11144

$$

MCT

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 2, 5:20 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino, Yavapai3 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.