Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 174, NWS Flagstaff, AZ

August 13, 2021Gila County, Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 13, 2021, 8:15 PM MST for Gila County, Yavapai County, Arizona. It was in force for 2 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 13, 2021, 8:15 PM MST (03:15 UTC)
Expired: Aug 13, 2021, 10:15 PM MST
In force: 2 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Gila County, AZ, Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 47 km from the middle of the area, began a volume at 03:15 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, 3.3 hours before the alert went out and 96 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: 430 J/kg
Mixed-layer CIN: -94 J/kg
Mixed-layer LCL: 1694 m above ground
0-6 km bulk shear: 7 kt
0-1 km storm-relative helicity: 22 m²/s²
0-3 km storm-relative helicity: 170 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

415 
WGUS55 KFGZ 140315
FFWFGZ
AZC007-025-140515-
/O.NEW.KFGZ.FF.W.0174.210814T0315Z-210814T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
815 PM MST Fri Aug 13 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  The Backbone Fire scar in...
  Gila County in east central Arizona...
  Yavapai County in west central Arizona...

* Until 1015 PM MST.

* At 815 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain over the Backbone Fire scar. 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 Backbone
           Fire scar.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of areas in and around
           the Backbone Fire scar.

* Some locations that will experience flash flooding include...
  mainly rural areas of Gila and Yavapai Counties

This includes the following swimming holes...
All swimming holes and waterfalls on Fossil Creek and Fossil Creek 
Dam aka The Toilet Bowl.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get to higher ground immediately and stay away from Fossil Creek! 
Flash flood waters and debris will inundate swimming holes and 
recreation trails crossing washes within and downstream of the 
Backbone Fire scar.

&&

LAT...LON 3442 11170 3446 11155 3441 11155 3435 11162
      3430 11167 3430 11168 3430 11169 3437 11168
      3440 11170

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

$$

McCollum

2 follow-up statements

264 
WGUS75 KFGZ 140357
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
857 PM MST Fri Aug 13 2021

AZC007-025-140515-
/O.CON.KFGZ.FF.W.0174.000000T0000Z-210814T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-Yavapai AZ-
857 PM MST Fri Aug 13 2021

...FLASH FLOOD WARNING FOR THE BACKBONE FIRE SCAR REMAINS IN EFFECT 
UNTIL 1015 PM MST THIS EVENING FOR GILA AND YAVAPAI COUNTIES...

At 855 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain over the Backbone Fire scar were beginning to move out of the 
area. Lighter showers will continue through 9:00 PM. Between 0.75 
and 1.75 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 Backbone Fire scar.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of areas in and around
         the Backbone Fire scar.

Some locations that will experience flash flooding include...
  mainly rural areas of Gila and Yavapai Counties

This includes the following swimming holes...
All swimming holes and waterfalls on Fossil Creek and Fossil Creek 
Dam aka The Toilet Bowl.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Get to higher ground immediately and stay away from Fossil Creek! 
Flash flood waters and debris will inundate swimming holes and 
recreation trails crossing washes within and downstream of the 
Backbone Fire scar.

&&

LAT...LON 3442 11170 3446 11155 3441 11155 3435 11162
      3430 11167 3430 11168 3430 11169 3437 11168
      3440 11170

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

$$

McCollum

271 
WGUS75 KFGZ 140510
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
1010 PM MST Fri Aug 13 2021

AZC007-025-140520-
/O.EXP.KFGZ.FF.W.0174.000000T0000Z-210814T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-Yavapai AZ-
1010 PM MST Fri Aug 13 2021

...FLASH FLOOD WARNING FOR THE BACKBONE FIRE SCAR WILL EXPIRE AT 
1015 PM MST THIS EVENING FOR GILA AND YAVAPAI COUNTIES...

The heavy rain has ended over the Backbone Fire Scar. Flash flooding 
is no longer expected to pose a threat.

A Flash Flood Watch remains in effect until 200 AM MST for portions 
of east central Arizona and west central Arizona.

LAT...LON 3442 11170 3446 11155 3441 11155 3435 11162
      3430 11167 3430 11168 3430 11169 3437 11168
      3440 11170

$$

McCollum

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 13, 5:41 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	21 min
Aug 13, 6:09 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	25 min
Aug 13, 6:18 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	27 min
Aug 13, 7:00 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	15 min
Aug 13, 7:39 PM MST	Severe Thunderstorm Warning	FGZ	Gila	26 min
Aug 13, 8:09 PM MST	Severe Thunderstorm Warning	FGZ	Coconino	36 min
Aug 13, 8:38 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	52 min
Aug 13, 9:03 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	42 min
Aug 13, 9:43 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	47 min
Aug 13, 9:51 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Aug 13, 10:07 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	53 min
Aug 14, 3:06 PM MST	Severe Thunderstorm Warning	FGZ	Gila	39 min
Aug 14, 3:42 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Navajo	36 min
Aug 14, 3:58 PM MST	Severe Thunderstorm Warning	FGZ	Gila	29 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.