Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 167, NWS Flagstaff, AZ

August 11, 2021Yavapai County, Arizona

NWS Flagstaff, AZ issued this flash flood warning at Aug 11, 2021, 1:38 PM MST for Yavapai 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 11, 2021, 1:38 PM MST (20:38 UTC)
Expired
Aug 11, 2021, 4:45 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), 172 km from the middle of the area, began a volume at 20:40 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, 8.6 hours before the alert went out and 122 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 2021-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 82 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 2021-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 84 square meters per square second.193958Sfc1 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
82 J/kg
Mixed-layer CIN
-165 J/kg
Mixed-layer LCL
1265 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
84 m²/s²
0-3 km storm-relative helicity
153 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

456 
WGUS55 KFGZ 112038
FFWFGZ
AZC025-112345-
/O.NEW.KFGZ.FF.W.0167.210811T2038Z-210811T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Flagstaff AZ
138 PM MST Wed Aug 11 2021

The National Weather Service in Flagstaff has issued a

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

* Until 445 PM MST.

* At 137 PM MST, Doppler radar 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 inch 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.

  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

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.

&&

LAT...LON 3495 11309 3492 11294 3483 11290 3469 11300
      3470 11312 3478 11321

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

$$

EL
2 follow-up statements
487 
WGUS75 KFGZ 112102
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
202 PM MST Wed Aug 11 2021

AZC025-112345-
/O.CON.KFGZ.FF.W.0167.000000T0000Z-210811T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
202 PM MST Wed Aug 11 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 PM MST THIS 
AFTERNOON FOR YAVAPAI COUNTY...

At 200 PM MST, Doppler radar indicated that the heavy rainfall 
produced by thunderstorms has decreased in intensity across the 
warned area. Flash flooding is still expected as water drains. 
Between 1 and 2 inches of rain have fallen.

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...
  mainly rural areas of Yavapai County

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.

&&

LAT...LON 3495 11309 3492 11294 3483 11290 3469 11300
      3470 11312 3478 11321

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

$$

EL
963 
WGUS75 KFGZ 112340
FFSFGZ

Flash Flood Statement
National Weather Service Flagstaff AZ
440 PM MST Wed Aug 11 2021

AZC025-112350-
/O.EXP.KFGZ.FF.W.0167.000000T0000Z-210811T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yavapai AZ-
440 PM MST Wed Aug 11 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 445 PM MST THIS AFTERNOON FOR 
YAVAPAI COUNTY...

The heavy rain has ended over western Yavapai County 20 miles north 
of Bagdad in the Santa Maria Mountains. Flooding is no longer 
expected to pose a threat. Please heed any road closures.

LAT...LON 3495 11309 3492 11294 3483 11290 3469 11300
      3470 11312 3478 11321

$$

McCollum

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 11, 9:30 AM MSTFlash Flood Warning Considerable damage threatFGZYavapai3 hr
Aug 11, 1:48 PM MSTFlash Flood Warning Considerable damage threatFGZCoconino3 hr
Aug 11, 2:25 PM MSTSpecial Weather StatementFGZ35 min
Aug 11, 2:49 PM MSTFlash Flood Warning Considerable damage threatFGZApache3 hr
Aug 11, 3:11 PM MSTSpecial Weather StatementFGZ34 min
Aug 11, 4:24 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.