Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 114, NWS Las Vegas, NV

August 12, 2021Mohave County, Arizona

NWS Las Vegas, NV issued this flash flood warning at Aug 12, 2021, 10:56 PM MST for Mohave 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 12, 2021, 10:56 PM MST (05:56 UTC)
Expired: Aug 13, 2021, 2:00 AM MST
In force: 3 hr
Issued by: NWS Las Vegas, NV
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Mohave County, AZ

The radar

The Las Vegas radar (KESX), 32 km from the middle of the area, began a volume at 05:56 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

Las Vegas, NV (KVEF), launched 00:00Z, 5.9 hours before the alert went out and 127 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: 1235 J/kg
Mixed-layer CIN: -41 J/kg
Mixed-layer LCL: 2944 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 2 m²/s²
0-3 km storm-relative helicity: 96 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

508 
WGUS55 KVEF 130556
FFWVEF
AZC015-130900-
/O.NEW.KVEF.FF.W.0114.210813T0556Z-210813T0900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
1056 PM PDT Thu Aug 12 2021

The National Weather Service in Las Vegas has issued a

* Flash Flood Warning for...
  West Central Mohave County in northwestern Arizona...

* Until 200 AM MST.

* At 1056 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain west of Dolan Springs. Between 0.5 and 1.5 inches of 
  rain have fallen. Flash flooding is ongoing or expected to begin 
  shortly.  Heavy rainfall may continue to develop south to near 
  Katherine's Landing and northern parts of Golden Valley.

  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...
  Bullhead City and Katherine Landing.

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 3571 11469 3572 11454 3567 11448 3533 11433
      3522 11440 3520 11455 3523 11458 3535 11460
      3541 11463 3545 11466 3549 11468 3551 11468
      3554 11466 3558 11468 3559 11466 3561 11465
      3565 11469 3569 11468 3570 11470

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

$$

CO

2 follow-up statements

234 
WGUS75 KVEF 130724
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1224 AM PDT Fri Aug 13 2021

AZC015-130900-
/O.CON.KVEF.FF.W.0114.000000T0000Z-210813T0900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
1224 AM MST Fri Aug 13 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 2 AM MST EARLY THIS 
MORNING FOR WEST CENTRAL MOHAVE COUNTY...

At 1224 AM MST, A combination of radar estimates and rain gauge 
reports indicated thunderstorms producing heavy rain produced 
between 1 and 3 inches of rain has fallen. Flash flooding is likely 
ongoing.

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...
  Cottonwood Road, Arizona Bay Road, and washes on the east bank of 
  Lake Mohave from Windy Canyon to Katherine Landing.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Stay away or be swept away. Banks along washes and culverts can 
become unstable and unsafe.

Flooding is occurring or is imminent. It is important to know where 
you are relative to streams, rivers, or creeks which can become 
killers in heavy rains. Campers and hikers should avoid streams or 
creeks.

&&

LAT...LON 3571 11469 3572 11454 3567 11448 3533 11433
      3522 11440 3520 11455 3523 11458 3535 11460
      3541 11463 3545 11466 3549 11468 3551 11468
      3554 11466 3558 11468 3559 11466 3561 11465
      3565 11469 3569 11468 3570 11470

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

$$

TL

603 
WGUS75 KVEF 130901
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
201 AM PDT Fri Aug 13 2021

AZC015-130911-
/O.EXP.KVEF.FF.W.0114.000000T0000Z-210813T0900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
201 AM MST Fri Aug 13 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR WEST CENTRAL MOHAVE COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3571 11469 3572 11454 3567 11448 3533 11433
      3522 11440 3520 11455 3523 11458 3535 11460
      3541 11463 3545 11466 3549 11468 3551 11468
      3554 11466 3558 11468 3559 11466 3561 11465
      3565 11469 3569 11468 3570 11470

$$

TL

The office that day

Everything else NWS Las Vegas, NV issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 12, 5:24 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	111 min
Aug 12, 5:43 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	3 hr
Aug 12, 8:17 PM MST	Severe Thunderstorm Warning	VEF	Mohave	58 min
Aug 12, 8:42 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	3 hr
Aug 12, 8:54 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	3 hr
Aug 12, 9:10 PM MST	Severe Thunderstorm Warning	VEF	Mohave	50 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.