Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 113, NWS Las Vegas, NV

August 12, 2012San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Aug 12, 2012, 3:18 PM PDT for San Bernardino County, California. It was in force for 117 min. 3 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
Aug 12, 2012, 3:18 PM PDT (22:18 UTC)
Expired
Aug 12, 2012, 5:15 PM PDT
In force
117 min
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

County San Bernardino County, CA

The radar

The Santa Ana Mts radar (KSOX), 127 km from the middle of the area, began a volume at 22:18 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 12, 3:40 PM PDTFLASH FLOOD2 Se Landers (Ar190), CA6 INCHES OF FLOWING WATER ON AVALON AVE BETWEEN ABERDEEN DRIVE AND WINTERS DRIVE IN LANDERS. WATER CONTAINS ROCKS AND DEBRIS.
Aug 12, 4:19 PM PDTHEAVY RAIN 0.56 Nnw Landers (Ar190), CATRAINED SPOTTER REPORTED THAT 0.50 OF AN INCH OF RAIN FELL BETWEEN 345 PM AND 414 PM PDT. IT WAS STILL RAINING AT THE TIME OF THE REPORT.
Aug 12, 4:33 PM PDTFLASH FLOOD4 Nw Joshua Tree, CA8-10 INCHES OF SWIFT FLOWING WATER AT THE INTERSECTION OF YUCCA MESA RD AND BUENA VISTA DRIVE IN YUCCA VALLEY.

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

The nearest sounding before it

San Diego, CA (KNKX), launched 12:00Z, 10.3 hours before the alert went out and 175 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, San Diego, CA at 12:00Z on 2012-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 552 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, San Diego, CA at 12:00Z on 2012-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -9 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
552 J/kg
Mixed-layer CIN
-580 J/kg
Mixed-layer LCL
1680 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
-9 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

604 
WGUS55 KVEF 122218
FFWVEF
CAC071-130015-
/O.NEW.KVEF.FF.W.0113.120812T2218Z-120813T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
318 PM PDT SUN AUG 12 2012

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTH CENTRAL SAN BERNARDINO COUNTY IN SOUTHERN CALIFORNIA...

* UNTIL 515 PM PDT.

* AT 309 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR JOSHUA TREE...OR 15 MILES
  WEST OF TWENTYNINE PALMS. THE STORM PRODUCING VERY HEAVY RAIN WAS
  NEARLY STATIONARY.

* LOCATIONS IMPACTED INCLUDE...
  TWENTYNINE PALMS...YUCCA VALLEY...JOSHUA TREE LAKE CAMPGROUND.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED ON AREA ROADWAYS...AROUND UNDERPASSES...
AND IN NORMALLY DRY WASHES AND LOW LYING AREAS. FLASH FLOODING IS
NATURES NUMBER ONE KILLER. NEVER TRY TO CROSS A FLOODED ROADWAY OR
WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE...OR BY USING THE TWITTER HASHTAG...
NWSVEGAS.

&&

LAT...LON 3421 11643 3426 11644 3432 11647 3436 11639
      3426 11630 3420 11616 3412 11616 3413 11627
      3409 11627 3408 11628 3408 11640

$$

JS
2 follow-up statements
678 
WGUS75 KVEF 122325
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
425 PM PDT SUN AUG 12 2012

CAC071-130015-
/O.CON.KVEF.FF.W.0113.000000T0000Z-120813T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
425 PM PDT SUN AUG 12 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 515 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO COUNTY...

AT 417 PM PDT...TRAINED WEATHER SPOTTERS REPORTED A THUNDERSTORM 
PRODUCING FLASH FLOODING IN YUCCA VALLEY. THERE HAVE BEEN SEVERAL 
REPORTS OF SWIFT FLOWING WATER UP TO 10 INCHES ON SEVERAL ROADS 
BETWEEN LANDERS AND YUCCA VALLEY. ROCKS AND DEBRIS HAVE ALSO BEEN 
DEPOSITED ON ROADWAYS BY THE SWIFT FLOWING WATER. THIS STORM WAS 
LOCATED NEAR JOSHUA TREE...OR 16 MILES WEST OF TWENTYNINE 
PALMS...MOVING SOUTH AT 5 MPH.

LOCATIONS IMPACTED INCLUDE...LANDERS...YUCCA MESA...YUCCA VALLEY AND
JOSHUA TREE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED ON AREA ROADWAYS...AROUND UNDERPASSES...
AND IN NORMALLY DRY WASHES AND LOW LYING AREAS. FLASH FLOODING IS
NATURES NUMBER ONE KILLER. NEVER TRY TO CROSS A FLOODED ROADWAY OR
WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE...OR BY USING THE TWITTER HASHTAG...
NWSVEGAS.

&&

LAT...LON 3421 11643 3426 11644 3432 11647 3436 11639
      3426 11630 3420 11616 3412 11616 3413 11627
      3409 11627 3408 11628 3408 11640

$$

PIERCE
991 
WGUS75 KVEF 130018
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
518 PM PDT SUN AUG 12 2012

CAC071-130026-
/O.EXP.KVEF.FF.W.0113.000000T0000Z-120813T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
518 PM PDT SUN AUG 12 2012

...THE FLASH FLOOD WARNING HAS EXPIRED FOR SOUTH CENTRAL SAN
BERNARDINO COUNTY...

THUNDERSTORMS HAVE DISSIPATED AND THE WARNING HAS EXPIRED. MOTORISTS 
IN THE LANDERS AND YUCCA VALLEY AREA SHOULD USE CAUTION AS AREA 
ROADWAYS MAY STILL HAVE PONDING OF WATER IN LOW LYING AREAS.

LAT...LON 3421 11643 3426 11644 3432 11647 3436 11639
      3426 11630 3420 11616 3412 11616 3413 11627
      3409 11627 3408 11628 3408 11640

$$

JS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 1:41 PM PDTAreal Flood AdvisoryVEFInyo3 hr
Aug 12, 2:46 PM PDTFlash Flood WarningVEFSan Bernardino119 min

Nearby

Flash Flood Warnings in California, 2012Every flash flood warning in 2012

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.