Alert archive / California / Flash Flood Warnings in 2021

Flash Flood Warning 137, NWS Phoenix, AZ

August 10, 2021Imperial County, Riverside County, California; La Paz County, Yuma County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Aug 10, 2021, 7:33 PM PDT for Imperial County, Riverside County, California; La Paz County, Yuma County, Arizona. It was in force for 4 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, 7:33 PM PDT (02:33 UTC)
Expired: Aug 10, 2021, 11:30 PM PDT
In force: 4 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties La Paz County, AZ, Yuma County, AZ, Imperial County, CA, Riverside County, CA

The radar

The Yuma radar (KYUX), 114 km from the middle of the area, began a volume at 02:35 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
Aug 10, 9:05 PM PDT	FLASH FLOOD	Quartzsite, AZ	CORRECTS PREVIOUS FLASH FLOOD REPORT FROM QUARTZSITE. DELAYED REPORT SOCIAL MEDIA VIDEOS SHOWED 6-8 INCHES OF SWIFT FLOWING WATER OVER THE ROAD AT MOCKINGBIRD AND PLYMOUTH IN QUARTZSITE.

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

The nearest sounding before it

Phoenix, AZ (KPSR), launched 00:00Z, 2.6 hours before the alert went out and 230 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: 934 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 1571 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: -19 m²/s²
0-3 km storm-relative helicity: 0 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

512 
WGUS55 KPSR 110233
FFWPSR
AZC012-027-CAC025-065-110630-
/O.NEW.KPSR.FF.W.0137.210811T0233Z-210811T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Phoenix has issued a

* Flash Flood Warning for...
  North Central Yuma County in southwestern Arizona...
  Southwestern La Paz County in west central Arizona...
  Northeastern Imperial County in southeastern California...
  Riverside County in southern California...

* Until 1130 PM MST /1130 PM PDT/.

* At 733 PM MST /733 PM PDT/, Doppler radar indicated thunderstorms 
  producing heavy rain across the warned area. Between 0.5 and 1.5 
  inches of rain have fallen. 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 normally dry
           washes, urban areas, highways, streets and
           underpasses.

* Some locations that will experience flash flooding include...
  Quartzsite, Cibola, and Ehrenberg.

This includes the following highways...
	AZ Interstate 10 between mile marker 1 and 18.
	AZ Route 95 between mile markers 100 and 112.
	CA Interstate 10 between mile markers 155 and 156.

This includes the following streams and drainages...
  Goodman Wash, Petes Wash, Bouse Wash, Scaddan Wash, La Paz Wash,  
  Plomosa Wash, Tyson Wash, Mohave Wash, Ehrenberg Wash, Lopez Wash, 
  French Creek, Poormans Wash and Limekiln Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3325 11477 3342 11467 3393 11440 3386 11403
      3334 11405

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

$$

AJ

2 follow-up statements

597 
WGUS75 KPSR 110311
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
811 PM MST Tue Aug 10 2021

AZC027-110321-
/O.CAN.KPSR.FF.W.0137.000000T0000Z-210811T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yuma AZ-
811 PM MST Tue Aug 10 2021

...FLASH FLOOD WARNING IS CANCELLED FOR LA PAZ, IMPERIAL AND 
RIVERSIDE COUNTIES...

Flooding is no longer expected to pose a threat. Please continue to 
heed remaining road closures.

LAT...LON 3325 11477 3342 11467 3393 11440 3386 11403
      3334 11405

$$

AZC012-CAC025-065-110630-
/O.CON.KPSR.FF.W.0137.000000T0000Z-210811T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
La Paz AZ-Imperial CA-Riverside CA-
811 PM MST Tue Aug 10 2021 /811 PM PDT Tue Aug 10 2021/

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1130 PM MST/PDT/ THIS 
EVENING FOR SOUTHWESTERN LA PAZ, NORTHEASTERN IMPERIAL AND RIVERSIDE 
COUNTIES...

At 811 PM MST /811 PM PDT/, Doppler radar indicated thunderstorms 
producing heavy rain across the warned area. Between 1 and 2 inches 
of rain have fallen. 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 normally dry washes,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Quartzsite, Cibola, and Ehrenberg.

This includes the following highways...
	AZ Interstate 10 between mile marker 1 and 18.
	AZ Route 95 between mile markers 100 and 112.
	

This includes the following streams and drainages...
  Red Raven Wash, Goodman Wash, Petes Wash, Bouse Wash, Scaddan 
  Wash, Kaiser Wash, Paz Wash, La, Crazy Woman Wash, Cholla Wash, 
  La, Gould Wash, Hart Mine Wash, Mule Wash, Colorado River, 
  Milpitas Wash, Weaver Wash, Smith Wash, Lake Wash, Apache Wash, 
  Plomosa Wash, Tyson Wash, Mohave Wash, Ehrenberg Wash, Lopez Wash, 
  Cave Creek, Hoodoo Wash, French Creek, Poormans Wash and Limekiln 
  Wash.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3325 11477 3342 11467 3393 11440 3386 11403
      3334 11405

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

$$

AJ

224 
WGUS75 KPSR 110633
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1133 PM MST Tue Aug 10 2021

AZC012-CAC025-065-110643-
/O.EXP.KPSR.FF.W.0137.000000T0000Z-210811T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
La Paz AZ-Imperial CA-Riverside CA-
1133 PM MST Tue Aug 10 2021 /1133 PM PDT Tue Aug 10 2021/

...FLASH FLOOD WARNING HAS EXPIRED FOR SOUTHWESTERN LA PAZ, 
NORTHEASTERN IMPERIAL AND RIVERSIDE COUNTIES...

The heaviest rain has ended and flash flooding is generally not 
anticipated. However, localized flooding may persist overnight, 
particularly near Tyson Wash in Quartzsite. Please continue to heed 
remaining road closures.

LAT...LON 3325 11477 3342 11467 3393 11440 3386 11403
      3334 11405

$$

Hirsch

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 10, 6:30 PM PDT	Severe Thunderstorm Warning	PSR	Riverside	45 min
Aug 10, 7:15 PM PDT	Dust Storm Warning	PSR	Imperial, Riverside, San Bernardino	60 min
Aug 10, 7:26 PM PDT	Severe Thunderstorm Warning	PSR	Imperial, Riverside	49 min
Aug 10, 8:18 PM PDT	Severe Thunderstorm Warning	PSR	Imperial, Riverside	57 min
Aug 10, 8:38 PM PDT	Dust Storm Warning	PSR	Imperial, Riverside	52 min
Aug 10, 9:08 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Imperial, Riverside	6 hr
Aug 10, 9:42 PM PDT	Dust Storm Warning	PSR	Imperial	93 min
Aug 10, 9:54 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Riverside	86 min
Aug 10, 11:16 PM PDT	Special Weather Statement	PSR	Imperial	74 min
Aug 11, 2:01 PM PDT	Dust Storm Advisory	PSR	Imperial	59 min
Aug 10, 5:23 PM PDT	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 10, 5:35 PM PDT	Special Weather Statement	PSR		40 min
Aug 10, 5:51 PM PDT	Areal Flood Advisory	PSR	La Paz	3 hr
Aug 10, 5:55 PM PDT	Special Weather Statement	PSR	La Paz	50 min
Aug 10, 6:36 PM PDT	Flash Flood Warning Considerable damage threat	PSR	La Paz, Maricopa	4 hr
Aug 10, 7:43 PM PDT	Dust Storm Advisory	PSR	Maricopa, Pinal, Yuma	62 min
Aug 10, 9:12 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Maricopa, Yuma	6 hr
Aug 10, 9:23 PM PDT	Special Weather Statement	PSR	Yuma	97 min
Aug 10, 10:35 PM PDT	Flash Flood Warning Considerable damage threat	PSR	La Paz, Maricopa, Yuma	6 hr
Aug 11, 12:01 AM PDT	Flash Flood Warning Considerable damage threat	PSR	La Paz, Yuma	5 hr
Aug 11, 2:00 AM PDT	Areal Flood Advisory	PSR	Gila	3 hr
Aug 11, 3:29 AM PDT	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 4:33 AM PDT	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Aug 11, 6:06 AM PDT	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 6:11 AM PDT	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Aug 11, 6:15 AM PDT	Areal Flood Advisory	PSR	Gila, Maricopa	3 hr
Aug 11, 7:30 AM PDT	Flash Flood Warning Considerable damage threat	PSR	Gila, Maricopa	6 hr
Aug 11, 7:46 AM PDT	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Aug 11, 8:12 AM PDT	Flash Flood Warning Considerable damage threat	PSR	Maricopa, Pinal	6 hr
Aug 11, 9:13 AM PDT	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 1:01 PM PDT	Special Weather Statement	PSR	Yuma	59 min
Aug 11, 1:29 PM PDT	Areal Flood Warning	PSR	Maricopa	6 hr
Aug 11, 1:43 PM PDT	Areal Flood Warning	PSR	Gila	4 hr
Aug 11, 1:49 PM PDT	Areal Flood Advisory	PSR	Yuma	3 hr
Aug 11, 2:17 PM PDT	Severe Thunderstorm Warning	PSR	Yuma	43 min
Aug 11, 3:02 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Yuma	4 hr
Aug 11, 3:11 PM PDT	Special Weather Statement	PSR		64 min
Aug 11, 3:29 PM PDT	Special Weather Statement	PSR	Maricopa	46 min
Aug 11, 3:34 PM PDT	Special Weather Statement	PSR		56 min
Aug 11, 3:44 PM PDT	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 3:47 PM PDT	Areal Flood Advisory	PSR	Maricopa	14 min
Aug 11, 3:50 PM PDT	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 4:01 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Maricopa	3 hr
Aug 11, 4:33 PM PDT	Areal Flood Advisory	PSR	Maricopa	3 hr
Aug 11, 4:44 PM PDT	Dust Storm Advisory	PSR	Maricopa, Pinal	61 min
Aug 11, 4:56 PM PDT	Flash Flood Warning Considerable damage threat	PSR	Maricopa	3 hr

Nearby

Flash Flood Warnings in California, 2021 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.