Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 82, NWS Flagstaff, AZ

July 22, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 22, 2021, 3:31 PM MST for Coconino County, Arizona. It was in force for 115 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Jul 22, 2021, 3:31 PM MST (22:31 UTC)
Expired: Jul 22, 2021, 5:26 PM MST
In force: 115 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), 135 km from the middle of the area, began a volume at 22:31 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

Time	Report	Where	Remark
Jul 22, 3:45 PM MST	FLASH FLOOD	7 Sw Marble Canyon, AZ	FLASH FLOODING REPORTED IN SOAP CREEK AND JACKASS CANYONS, AND OTHER AREA SLOT CANYONS.

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

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 10.5 hours before the alert went out and 173 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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.

526 
WGUS55 KFGZ 222231
FFWFGZ
AZC005-230130-
/O.NEW.KFGZ.FF.W.0082.210722T2231Z-210723T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Coconino County in north central Arizona...

* Until 630 PM MST.

* At 328 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain over the Highway 89A area just south and west of Marble 
  Canyon. Storms are also crossing Highway 89 just north of Bitter 
  Springs. Between 0.75 and 1.5 inches of rain have fallen. 
  Additional rainfall amounts of 0.5 to 1 inch are possible in the 
  warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Life-threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life-threatening flash flooding of low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  Grand Canyon National Park and Navajo Reservation.

This includes the following slot canyons...
	Tanner Wash.

This includes the following highways...
	U.S. Highway 89 between mile markers 528 and 535.
	U.S. Highway 89A between mile markers 526 and 535...and
	between mile markers 540 and 549.

This includes the following streams and drainages...
  South Fork Soap Creek, Badger Canyon, Tanner Wash, Soap Creek, 
  Jackass Creek, Colorado River and Fall Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3682 11188 3685 11182 3688 11178 3684 11169
      3674 11154 3669 11157 3664 11168

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

$$

JJ

2 follow-up statements

386 
WGUS75 KFGZ 222353
FFSFGZ

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

AZC005-230130-
/O.CON.KFGZ.FF.W.0082.000000T0000Z-210723T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
453 PM MST Thu Jul 22 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM MST THIS 
EVENING FOR COCONINO COUNTY...

At 451 PM MST, Heavy rain has ended over the Highway 89A area just 
south and west of Marble Canyon. Between 0.75 and 1.5 inches of rain 
fell earlier this afternoon. Additional rainfall amounts of 0.5 to 1 
inch are possible in the warned area. Flash flooding is ongoing or 
expected to begin shortly.

HAZARD...Life-threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life-threatening flash flooding of low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  Grand Canyon National Park and Navajo Reservation.

This includes the following slot canyons...
	Tanner Wash.

This includes the following highways...
	U.S. Highway 89 between mile markers 528 and 535.
	U.S. Highway 89A between mile markers 526 and 535...and
	between mile markers 540 and 548.

This includes the following streams and drainages...
  Paria River, South Fork Soap Creek, Badger Canyon, Tanner Wash, 
  Soap Creek, Jackass Creek, Colorado River and Fall Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Remain alert for flooding even in locations not receiving rain. 
Normally dry washes, slot canyons and creeks can become raging 
killer currents in a matter of minutes, even from distant rainfall.

&&

LAT...LON 3682 11188 3685 11182 3688 11178 3684 11169
      3674 11154 3669 11157 3664 11168

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

$$

JJ

493 
WGUS75 KFGZ 230026
FFSFGZ

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

AZC005-230036-
/O.CAN.KFGZ.FF.W.0082.000000T0000Z-210723T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
526 PM MST Thu Jul 22 2021

...FLASH FLOOD WARNING IS CANCELLED FOR COCONINO COUNTY...

Flood waters have receded and heavy rain has ended in the Marble 
Canyon Area. Flooding is no longer expected to pose a threat. Please 
continue to heed remaining road closures.

LAT...LON 3682 11188 3685 11182 3688 11178 3684 11169
      3674 11154 3669 11157 3664 11168

$$

McCollum

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 6:38 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila	3 hr
Jul 21, 6:53 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	112 min
Jul 22, 12:28 PM MST	Areal Flood Advisory	FGZ	Coconino	3 hr
Jul 22, 2:10 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Jul 22, 3:01 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	44 min
Jul 22, 3:58 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Navajo	3 hr
Jul 22, 4:04 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	116 min

Nearby

Flash Flood Warnings in Arizona, 2021 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.