Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 164, NWS Flagstaff, AZ

August 10, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 10, 2021, 3:46 PM MST for Yavapai County, Arizona. It was in force for 3 hr. 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
Aug 10, 2021, 3:46 PM MST (22:46 UTC)
Expired
Aug 10, 2021, 6:45 PM MST
In force
3 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), 130 km from the middle of the area, began a volume at 22:50 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

TimeReportWhereRemark
Aug 10, 4:30 PM MSTFLASH FLOOD1 Sw Wilhoit, AZROAD CLOSED NEAR WILHOIT PUBLIC LIBRARY DUE TO FLOODING. ADDITIONAL ROAD CLOSURES FROM FLOODING ALONG WALDEN BLVD.

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, 10.8 hours before the alert went out and 117 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-pSkew-T log-p diagram, Flgstf/Belemont, AZ at 12:00Z on 2021-08-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 609 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Flgstf/Belemont, AZ at 12:00Z on 2021-08-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
609 J/kg
Mixed-layer CIN
-55 J/kg
Mixed-layer LCL
962 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
118 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

445 
WGUS55 KFGZ 102246
FFWFGZ
AZC025-110145-
/O.NEW.KFGZ.FF.W.0164.210810T2246Z-210811T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
346 PM MST Tue Aug 10 2021

The National Weather Service in Flagstaff has issued a

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

* Until 645 PM MST.

* At 345 PM MST, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  1 and 2 inches of rain have fallen. Additional rainfall amounts of 
  0.5 to 1.5 inches 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 and automated gauges.

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

* Some locations that will experience flash flooding include...
  Wilhoit, Kirkland, Skull Valley and Walker.

This includes the following highways...
	State Route 89 between mile markers 282 and 300.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

&&

LAT...LON 3458 11257 3453 11257 3444 11253 3444 11246
      3447 11237 3445 11235 3438 11239 3433 11244
      3430 11250 3428 11265 3427 11272 3431 11276
      3434 11278 3437 11282 3441 11285 3451 11285

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

$$

Humphreys
2 follow-up statements
149 
WGUS75 KFGZ 102348
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
448 PM MST Tue Aug 10 2021

AZC025-110145-
/O.CON.KFGZ.FF.W.0164.000000T0000Z-210811T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
448 PM MST Tue Aug 10 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 645 PM MST THIS 
EVENING FOR YAVAPAI COUNTY...

At 447 PM MST, Heavy rainfall has ended over the warned area. Flash 
flooding will still remain a threat while flood waters recede.

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

SOURCE...Radar and automated gauges.

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

Some locations that will experience flash flooding include...
  Wilhoit, Kirkland, Skull Valley and Walker.

This includes the following highways...
	State Route 89 between mile markers 282 and 300.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Flooding of washes and creeks will occur, some dirt roads will 
become muddy and impassable. Paved roads and underpasses could 
become flooded as well.

In hilly or mountainous terrain, there are many low water crossings 
which will become dangerous in heavy rain. Do not attempt to cross 
flooded roads. Find an alternate route.

&&

LAT...LON 3458 11257 3453 11257 3444 11253 3444 11246
      3447 11237 3445 11235 3438 11239 3433 11244
      3430 11250 3428 11265 3427 11272 3431 11276
      3434 11278 3437 11282 3441 11285 3451 11285

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

$$

Humphreys
242 
WGUS75 KFGZ 110136
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
636 PM MST Tue Aug 10 2021

AZC025-110146-
/O.EXP.KFGZ.FF.W.0164.000000T0000Z-210811T0145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
636 PM MST Tue Aug 10 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 645 PM MST THIS EVENING FOR 
YAVAPAI COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures and use 
caution near any creeks or washes running high this evening.

LAT...LON 3458 11257 3453 11257 3444 11253 3444 11246
      3447 11237 3445 11235 3438 11239 3433 11244
      3430 11250 3428 11265 3427 11272 3431 11276
      3434 11278 3437 11282 3441 11285 3451 11285

$$

MCT

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 9, 5:19 PM MSTSpecial Weather StatementFGZ41 min
Aug 9, 6:17 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai3 hr
Aug 9, 6:56 PM MSTSevere Thunderstorm WarningFGZYavapai34 min
Aug 9, 7:27 PM MSTSpecial Weather StatementFGZ33 min
Aug 9, 7:50 PM MSTSpecial Weather StatementFGZGila25 min
Aug 9, 8:44 PM MSTSpecial Weather StatementFGZGila46 min
Aug 9, 9:18 PM MSTAreal Flood AdvisoryFGZGila, Navajo3 hr
Aug 9, 9:32 PM MSTSpecial Weather StatementFGZGila43 min
Aug 10, 11:35 AM MSTSpecial Weather StatementFGZ25 min
Aug 10, 11:55 AM MSTSevere Thunderstorm WarningFGZCoconino15 min
Aug 10, 12:02 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino3 hr
Aug 10, 12:14 PM MSTSpecial Weather StatementFGZ31 min
Aug 10, 12:46 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino3 hr
Aug 10, 12:59 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino, Yavapai3 hr
Aug 10, 1:22 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino, Yavapai53 min
Aug 10, 2:22 PM MSTSpecial Weather StatementFGZYavapai23 min
Aug 10, 2:26 PM MSTSevere Thunderstorm WarningFGZYavapai32 min
Aug 10, 2:35 PM MSTSevere Thunderstorm WarningFGZYavapai40 min
Aug 10, 2:43 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai3 hr
Aug 10, 2:52 PM MSTSevere Thunderstorm WarningFGZCoconino, Yavapai38 min
Aug 10, 3:11 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino, Yavapai3 hr
Aug 10, 4:13 PM MSTFlash Flood Warning Considerable damage threatFGZYavapai3 hr

Nearby

Flash Flood Warnings in Arizona, 2021Every 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.