Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 141, NWS Flagstaff, AZ

August 1, 2021Coconino County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 1, 2021, 5:22 PM MST for Coconino 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: Aug 1, 2021, 5:22 PM MST (00:22 UTC)
Expired: Aug 1, 2021, 8:30 PM MST
In force: 3 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), 164 km from the middle of the area, began a volume at 00:26 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, 0.4 hours before the alert went out and 199 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: 916 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 1422 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 3 m²/s²
0-3 km storm-relative helicity: 41 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.4

Open this sounding in Storm Lab

The text

As transmitted.

718 
WGUS55 KFGZ 020022
FFWFGZ
AZC005-020330-
/O.NEW.KFGZ.FF.W.0141.210802T0022Z-210802T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
522 PM MST Sun Aug 1 2021

The National Weather Service in Flagstaff has issued a

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

* Until 830 PM MST.

* At 520 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 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.

  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...
  Glen Canyon National Recreation Area and Lake Powell.

This includes the following slot canyons...
	Labyrinth Canyon.

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.

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

&&

LAT...LON 3700 11105 3689 11113 3688 11120 3692 11128
      3694 11130 3700 11135

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

$$

TM

2 follow-up statements

779 
WGUS75 KFGZ 020129
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
629 PM MST Sun Aug 1 2021

AZC005-020330-
/O.CON.KFGZ.FF.W.0141.000000T0000Z-210802T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
629 PM MST Sun Aug 1 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 830 PM MST THIS 
EVENING FOR COCONINO COUNTY NEAR LABRYINTH CANYON...

At 626 PM MST, Doppler radar indicated thunderstorms have moved out 
of the area. However, 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.

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...
  Glen Canyon National Recreation Area and Lake Powell.

This includes the following slot canyons...
	Labyrinth Canyon.

This includes the following streams and drainages...
  Navajo Creek and West Canyon Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

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

&&

LAT...LON 3700 11105 3689 11113 3688 11120 3692 11128
      3694 11130 3700 11135

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

$$

TM

319 
WGUS75 KFGZ 020322
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
822 PM MST Sun Aug 1 2021

AZC005-020332-
/O.EXP.KFGZ.FF.W.0141.000000T0000Z-210802T0330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Coconino AZ-
822 PM MST Sun Aug 1 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 830 PM MST THIS EVENING FOR 
COCONINO COUNTY...

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

LAT...LON 3700 11105 3689 11113 3688 11120 3692 11128
      3694 11130 3700 11135

$$

Humphreys

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 1, 5:05 PM MST	Areal Flood Advisory	FGZ	Coconino	3 hr
Aug 1, 5:11 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Navajo	49 min
Aug 1, 5:28 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila, Navajo	5 hr
Aug 1, 5:49 PM MST	Areal Flood Advisory	FGZ	Coconino	3 hr
Aug 1, 5:49 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache, Navajo	3 hr
Aug 1, 6:04 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Coconino	3 hr
Aug 1, 6:20 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila, Navajo	3 hr
Aug 1, 7:55 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Gila	2 hr
Aug 1, 8:26 PM MST	Flash Flood Warning	FGZ	Gila	115 min
Aug 1, 8:59 PM MST	Flash Flood Warning	FGZ	Gila	85 min
Aug 1, 9:47 PM MST	Special Weather Statement	FGZ		28 min
Aug 2, 1:59 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Apache	3 hr
Aug 2, 2:23 PM MST	Severe Thunderstorm Warning	FGZ	Apache, Navajo	22 min
Aug 2, 2:44 PM MST	Severe Thunderstorm Warning	FGZ	Apache, Navajo	31 min
Aug 2, 4:06 PM MST	Special Weather Statement	FGZ	Apache	39 min
Aug 2, 4:14 PM MST	Special Weather Statement	FGZ		31 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.