Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 229, NWS Flagstaff, AZ

September 26, 2021Coconino County, Navajo County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Sep 26, 2021, 10:34 AM MST for Coconino County, Navajo County, Arizona. It was in force for 3 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 26, 2021, 10:34 AM MST (17:34 UTC)
Expired: Sep 26, 2021, 1:30 PM MST
In force: 3 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Coconino County, AZ, Navajo County, AZ

The radar

The Flagstaff radar (KFSX), 54 km from the middle of the area, began a volume at 17:33 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, 5.6 hours before the alert went out and 99 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: 14 J/kg
Mixed-layer CIN: -123 J/kg
Mixed-layer LCL: 1029 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: -26 m²/s²
0-3 km storm-relative helicity: 139 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

071 
WGUS55 KFGZ 261734
FFWFGZ
AZC005-017-262030-
/O.NEW.KFGZ.FF.W.0229.210926T1734Z-210926T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
1034 AM MST Sun Sep 26 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Jacks Canyon south of Winslow in...
  Coconino County in north central Arizona and...
  Navajo County in north central Arizona...

* Until 130 PM MST.

* At 1032 AM MST, gauge reports indicated heavy rain falling in 
  Jacks Canyon. Additional rainfall amounts of 0.25 to 0.75 inches 
  are possible in the warned area. Flash flooding is already 
  occurring.

  HAZARD...Life-threatening flash flooding produced by heavy
           rain.

  SOURCE...Gauges reported.

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

* Some locations that will experience flash flooding include...
  mainly rural areas of Coconino and Navajo Counties south of 
  Winslow.

This includes the following highways...
	State Route 99 near mile marker 39.
	State Route 87 between mile markers 326 and 337.

This includes the following creeks, washes and rivers...
  Clear Creek and Jacks Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Get out of washes and creeks if you are camping or hiking! Flooding 
is occurring or imminent and will inundate area drainages.

&&

LAT...LON 3484 11089 3489 11092 3493 11084 3496 11075
      3499 11066 3498 11065 3495 11068 3491 11075

FLASH FLOOD...GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

NL

2 follow-up statements

884 
WGUS75 KFGZ 261846
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
1146 AM MST Sun Sep 26 2021

AZC005-017-262030-
/O.CON.KFGZ.FF.W.0229.000000T0000Z-210926T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-Navajo AZ-
1146 AM MST Sun Sep 26 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 130 PM MST THIS 
AFTERNOON FOR JACKS CANYON SOUTH OF WINSLOW IN COCONINO AND NAVAJO 
COUNTIES...

At 1142 AM MST, Doppler radar and gauge reports indicated that 
moderate rain was still falling in the Jacks Canyon drainage basin. 
Additional rainfall amounts of 0.1 to 0.3 inches are possible in the 
warned area over the next hour. Flash flooding is already occurring.

HAZARD...Life-threatening flash flooding produced by heavy rain.

SOURCE...Gauges reported.

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

Some locations that will experience flash flooding include...
  mainly rural areas of Coconino and Navajo Counties south of 
  Winslow.

This includes the following highways...
	State Route 99 near mile marker 39.
	State Route 87 between mile markers 326 and 337.

This includes the following creeks, washes and rivers...
  Clear Creek and Jacks Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Get out of washes and creeks if you are camping or hiking! Flooding 
is occurring or imminent and will inundate area drainages.

&&

LAT...LON 3484 11089 3489 11092 3493 11084 3496 11075
      3499 11066 3498 11065 3495 11068 3491 11075

FLASH FLOOD...GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

NL

311 
WGUS75 KFGZ 262024
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
124 PM MST Sun Sep 26 2021

AZC005-017-262034-
/O.EXP.KFGZ.FF.W.0229.000000T0000Z-210926T2030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-Navajo AZ-
124 PM MST Sun Sep 26 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 130 PM MST THIS AFTERNOON FOR 
JACKS CANYON SOUTH OF WINSLOW IN COCONINO AND NAVAJO COUNTIES...

The heaviest rain has ended. Light to occasionally moderate rain 
will continue over the next few hours. River gauge data shows 
decreasing water levels in Jacks Canyon. Elevated flows will persist 
over the next hour or two this afternoon as a result, but the 
primary flood threat has ended. Continue to heed any road closures.

LAT...LON 3484 11089 3489 11092 3493 11084 3496 11075
      3499 11066 3498 11065 3495 11068 3491 11075

$$

NL

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 26, 11:28 AM MST	Areal Flood Advisory	FGZ	Gila	6 hr
Sep 26, 11:57 AM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	5 hr
Sep 26, 12:29 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Sep 26, 2:11 PM MST	Areal Flood Advisory	FGZ	Yavapai	3 hr
Sep 26, 2:23 PM MST	Special Weather Statement	FGZ		22 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.