Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 41, NWS Flagstaff, AZ

July 16, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Jul 16, 2021, 10:22 PM MST for Yavapai County, Arizona. It was in force for 6 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: Jul 16, 2021, 10:22 PM MST (05:22 UTC)
Expired: Jul 17, 2021, 4:15 AM MST
In force: 6 hr
Issued by: NWS Flagstaff, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Yavapai County, AZ

The radar

The Flagstaff radar (KFSX), 92 km from the middle of the area, began a volume at 05:25 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, 5.4 hours before the alert went out and 94 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: 347 J/kg
Mixed-layer CIN: -35 J/kg
Mixed-layer LCL: 1689 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 101 m²/s²
0-3 km storm-relative helicity: 82 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

667 
WGUS55 KFGZ 170522
FFWFGZ
AZC025-171115-
/O.NEW.KFGZ.FF.W.0041.210717T0522Z-210717T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
1022 PM MST Fri Jul 16 2021

The National Weather Service in Flagstaff has issued a

* Flash Flood Warning for...
  Yavapai County in west central Arizona...

* Until 415 AM MST.

* At 1016 PM MST, The river gauge on the Agua Fria River near 
  Humboldt reports a level of 10.97 feet from earlier thunderstorms 
  producing heavy rain across the warned area. Flash flooding is 
  ongoing and expected to begin shortly down stream.

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

  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...
  Agua Fria River in mainly rural areas of Yavapai County

This includes the following highways...
	State Route 69 between mile markers 280 and 281.
	Interstate 17 near mile marker 265.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3454 11225 3454 11223 3449 11222 3447 11222
      3445 11222 3445 11220 3444 11217 3433 11207
      3432 11208 3433 11210 3442 11218 3443 11220
      3444 11223 3447 11225 3449 11224

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

$$

MAS

2 follow-up statements

805 
WGUS75 KFGZ 170741
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
1241 AM MST Sat Jul 17 2021

AZC025-171115-
/O.CON.KFGZ.FF.W.0041.000000T0000Z-210717T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
1241 AM MST Sat Jul 17 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 AM MST EARLY THIS 
MORNING FOR YAVAPAI COUNTY...

At 1235 AM MST, river gauges on the Agua Fria River just east of 
Cordes Lakes indicated  a rise of more than 5 feet. This means the 
flood waters that originated near Dewey have reached east of I-17. 
Upstream guage reports show rapidly declining water levels.

Expect flood waters to travel south through the Agua Fria National 
Monument for the remainder of the night, with crest heights slowly 
diminishing over time.

HAZARD...Life-threatening flash flooding.

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 Yavapai County

This includes the following highways...
	Interstate 17 near mile marker 265.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3445 11220 3444 11217 3433 11207 3432 11208
      3433 11210 3442 11218 3443 11220

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

$$

Peterson

614 
WGUS75 KFGZ 171116
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
416 AM MST Sat Jul 17 2021

AZC025-171126-
/O.EXP.KFGZ.FF.W.0041.000000T0000Z-210717T1115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
416 AM MST Sat Jul 17 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR YAVAPAI COUNTY...

Expect flood waters to travel south through the Agua Fria National 
Monument for the remainder of the night, with crest heights slowly 
diminishing over time.

LAT...LON 3445 11220 3444 11217 3433 11207 3432 11208
      3433 11210 3442 11218 3443 11220

$$

Peterson

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 5:19 PM MST	Severe Thunderstorm Warning	FGZ	Yavapai	26 min
Jul 16, 5:30 PM MST	Severe Thunderstorm Warning	FGZ	Gila, Yavapai	26 min
Jul 16, 5:55 PM MST	Areal Flood Advisory	FGZ	Coconino, Gila, Yavapai	3 hr
Jul 16, 6:38 PM MST	Special Weather Statement	FGZ	Yavapai	52 min
Jul 16, 7:24 PM MST	Flash Flood Warning Considerable damage threat	FGZ	Yavapai	3 hr
Jul 17, 1:47 PM MST	Special Weather Statement	FGZ		28 min
Jul 17, 2:24 PM MST	Special Weather Statement	FGZ		21 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.