Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 47, NWS Las Vegas, NV

July 21, 2021Mohave County, Arizona

NWS Las Vegas, NV issued this flash flood warning at Jul 21, 2021, 4:56 PM MST for Mohave County, Arizona. It was in force for 3 hr. 2 reports 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: Jul 21, 2021, 4:56 PM MST (23:56 UTC)
Expired: Jul 21, 2021, 8:00 PM 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), 86 km from the middle of the area, began a volume at 23:51 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

Time	Report	Where	Remark
Jul 21, 5:16 PM MST	FLASH FLOOD	5 Sse Golden Valley, AZ	8 INCHES OF WATER FLOWING OVER AZTEC ROAD NEAR SHINARUMP DR.
Jul 21, 5:45 PM MST	FLASH FLOOD	5 Sse Golden Valley, AZ	18 INCHES OF WATER WITH DEBRIS FLOWING ACROSS AZTEC AND BACOBI ROADS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Las Vegas, NV (KVEF), launched 12:00Z, 11.9 hours before the alert went out and 180 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: 113 J/kg
Mixed-layer CIN: -279 J/kg
Mixed-layer LCL: 2504 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 34 m²/s²
0-3 km storm-relative helicity: 19 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

677 
WGUS55 KVEF 212356
FFWVEF
AZC015-220300-
/O.NEW.KVEF.FF.W.0047.210721T2356Z-210722T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
456 PM PDT Wed Jul 21 2021

The National Weather Service in Las Vegas has issued a

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

* Until 800 PM MST.

* At 456 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across 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...
  Golden Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3528 11414 3521 11411 3517 11411 3514 11412
      3504 11415 3503 11423 3514 11435 3527 11431
      3532 11418

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

$$

AN

2 follow-up statements

318 
WGUS75 KVEF 220157
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
657 PM PDT Wed Jul 21 2021

AZC015-220300-
/O.CON.KVEF.FF.W.0047.000000T0000Z-210722T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
657 PM MST Wed Jul 21 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 PM MST THIS EVENING 
FOR WEST CENTRAL MOHAVE COUNTY...

At 657 PM MST, Local county officials reported flash flooding 
impacts in Golden Valley over the last hour. Several area roads had 
water flowing over them as well as several locations with standing 
water. The heavy rain has ended in this area but continued flooding 
is expected to linger and could be a threat to travel.

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

SOURCE...Local county official reported.

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

Some locations that will experience flash flooding include...
  Golden Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3528 11414 3521 11411 3517 11411 3514 11412
      3504 11415 3503 11423 3514 11435 3527 11431
      3532 11418

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

TB

182 
WGUS75 KVEF 220254
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
754 PM PDT Wed Jul 21 2021

AZC015-220304-
/O.EXP.KVEF.FF.W.0047.000000T0000Z-210722T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
754 PM MST Wed Jul 21 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 8 PM MST THIS EVENING FOR WEST 
CENTRAL MOHAVE COUNTY...

Flood waters have receded according to local officials and the heavy 
rain has ended. Flooding is no longer expected to pose a threat. 
Please continue to heed remaining road closures.

LAT...LON 3528 11414 3521 11411 3517 11411 3514 11412
      3504 11415 3503 11423 3514 11435 3527 11431
      3532 11418

$$

TB

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 6:47 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	3 hr
Jul 21, 12:07 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	4 hr
Jul 21, 1:24 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	5 hr
Jul 21, 2:25 PM MST	Areal Flood Advisory	VEF	Mohave	2 hr
Jul 21, 3:35 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	3 hr
Jul 21, 4:03 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	2 hr
Jul 21, 4:18 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	2 hr

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.