Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 2, NWS Los Angeles, CA

September 9, 2012Los Angeles County, California

NWS Los Angeles, CA issued this flash flood warning at Sep 9, 2012, 5:22 PM PDT for Los Angeles County, California. It was in force for 3 hr. 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
Sep 9, 2012, 5:22 PM PDT (00:22 UTC)
Expired
Sep 9, 2012, 8:15 PM PDT
In force
3 hr
Issued by
NWS Los Angeles, CA
Area
Storm-based polygon
Flood severity
None

County Los Angeles County, CA

The radar

The Santa Ana Mts radar (KSOX), 70 km from the middle of the area, began a volume at 00:25 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
Sep 9, 5:24 PM PDTFLASH FLOOD4 E Pearblossom, CACALIFORNIA HIGHWAY PATROL IS REPORTING FLOODING ON HIGHWAY 138 AND 165TH ST E.
Sep 9, 5:27 PM PDTFLASH FLOOD3 Se Pearblossom, CACALIFORNIA HIGHWAY PATROL IS REPORTING A BOULDER ACROSS THE ROADWAY NEAR VALERMO AND FORT TEJON ROADS.
Sep 9, 5:47 PM PDTFLASH FLOOD4 E Pearblossom, CACALIFORNIA HIGHWAY PATROL REPORTS ALL EAST BOUND LANES ON HIGHWAY 138 BETWEEN 128TH EAST AND LONGVIEW EAST ARE UNDER WATER.

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 00:00Z, 0.4 hours before the alert went out and 190 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 00:00Z on 2012-09-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 137 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 00:00Z on 2012-09-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 67 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
137 J/kg
Mixed-layer CIN
-379 J/kg
Mixed-layer LCL
1160 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
67 m²/s²
0-3 km storm-relative helicity
107 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.

254 
WGUS56 KLOX 100022
FFWLOX
CAC037-100315-
/O.NEW.KLOX.FF.W.0002.120910T0022Z-120910T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE OXNARD CA
522 PM PDT SUN SEP 9 2012

THE NATIONAL WEATHER SERVICE IN OXNARD HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EAST CENTRAL LOS ANGELES COUNTY IN SOUTHWEST CALIFORNIA...

* UNTIL 815 PM PDT

* AT 513 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
FLASH FLOODING FROM A THUNDERSTORM 4 MILES SOUTHEAST OF 
PEARBLOSSOM...OR 10 MILES NORTH OF FALLING SPRINGS. NATIONAL WEATHER 
SERVICE DOPPLER RADAR ESTIMATES RAINFALL RATES BETWEEN 1 AND 2 
INCHES PER HOUR MAY HAVE FALLEN ACROSS THE AREA. FLOODING WILL LIKELY 
OCCUR ACROSS THE HIGHWAYS 2 AND 138.

* LOCATIONS IN THE WARNING INCLUDE PEARBLOSSOM AND CRYSTALAIRE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. NEVER DRIVE YOUR VEHICLE INTO
AREAS WHERE THE WATER COVERS THE ROADWAY. FLOOD WATERS ARE USUALLY
DEEPER THAN THEY APPEAR. JUST ONE FOOT OF FLOWING WATER IS POWERFUL
ENOUGH TO SWEEP VEHICLES OFF THE ROAD. WHEN ENCOUNTERING FLOODED
ROADS MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
OXNARD.

&&

LAT...LON 3431 11797 3454 11793 3456 11779 3436 11774

$$

HALL
3 follow-up statements
542 
WGUS76 KLOX 100107
FFSLOX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE OXNARD CA
607 PM PDT SUN SEP 9 2012

CAC037-100315-
/O.CON.KLOX.FF.W.0002.000000T0000Z-120910T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LOS ANGELES CA-
607 PM PDT SUN SEP 9 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM PDT FOR EAST
CENTRAL LOS ANGELES COUNTY...

AT 606 PM PDT...NATIONAL WEATHER SERVICE TRAINED WEATHER SPOTTERS 
AND CALIFORNIA HIGHWAY PATROL ARE REPORTING FLASH FLOODING FROM A 
THUNDERSTORM OVER THE WARNED AREA. FLASH FLOODING HAS BEEN REPORTED 
IN THE PEARBLOSSOM AND CRYSTALAIRE AREA OF THE ANTELOPE VALLEY 
FOOTHILLS...WITH WATER...MUD...AND ROCKS ACROSS HIGHWAY 138. TRAVEL 
ACROSS THE ANTELOPE VALLEY ALONG HIGHWAY 138 MAY BE DELAYED DUE TO 
FLOODING. PLEASE DELAY TRAVEL UNTIL FLOOD WATERS FROM THIS 
THUNDERSTORM HAVE RECEDED.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLOODING IS OCCURRING OR IS IMMINENT. MOST FLOOD RELATED DEATHS OCCUR
IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS WATER LOW WATER CROSSINGS.  
NEVER DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE 
ROADWAY. FLOOD WATERS ARE USUALLY DEEPER THAN THEY APPEAR. JUST ONE 
FOOT OF FLOWING WATER IS POWERFUL ENOUGH TO SWEEP VEHICLES OFF THE 
ROAD. WHEN ENCOUNTERING FLOODED ROADS MAKE THE SMART CHOICE...TURN 
AROUND...DONT DROWN.

NEVER TRY TO CROSS A FLOWING STREAM OR WASH...EVEN A SMALL ONE...ON 
FOOT. TO ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
OXNARD.

&&

LAT...LON 3431 11797 3454 11793 3456 11779 3436 11774

$$

HALL
950 
WGUS76 KLOX 100201
FFSLOX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE OXNARD CA
701 PM PDT SUN SEP 9 2012

CAC037-100315-
/O.CON.KLOX.FF.W.0002.000000T0000Z-120910T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LOS ANGELES CA-
701 PM PDT SUN SEP 9 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 815 PM PDT FOR EAST
CENTRAL LOS ANGELES COUNTY...

AT 701 PM PDT...NATIONAL WEATHER SERVICE TRAINED WEATHER SPOTTERS 
AND LOCAL LAW ENFORCEMENT OFFICIALS CONTINUE TO REPORT FLASH 
FLOODING OCCURRING IN THE ANTELOPE VALLEY THIS EVENING. CALIFORNIA 
HIGHWAY PATROL IS REPORTING A STRETCH OF HIGHWAY 138 NEAR 
PEARBLOSSOM UNDER WATER FROM PRIOR FLASH FLOODING. TRAVEL THROUGH 
THE EASTERN PORTION OF THE ANTELOPE VALLEY WILL LIKELY BE DELAYED 
DUE TO FLOODING OCCURRING ON AREA ROADWAYS. IT IS STRONGLY ADVISED 
TO DELAY TRAVEL UNTIL FLOOD WATERS HAVE RECEDED IN THE WARNING AREA.

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO PEARBLOSSOM 
AND CRYSTALAIRE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLOODING IS OCCURRING OR IS IMMINENT. MOST FLOOD RELATED DEATHS 
OCCUR IN AUTOMOBILES. DO NOT ATTEMPT TO CROSS WATER LOW WATER 
CROSSINGS. NEVER TRY TO CROSS A FLOWING ARROYO OR DRY WASH N FOOT. 
TO ESCAPE RISING WATER MOVE UP TO HIGHER GROUND.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE 
ROADWAY. MOST FLOOD DEATHS OCCUR IN AUTOMOBILES. THE WATER DEPTH MAY 
BE TOO GREAT TO ALLOW YOUR CAR TO CROSS SAFELY. JUST ONE FOOT OF 
FLOWING WATER IS POWERFUL ENOUGH TO SWEEP VEHICLES OFF THE ROAD. 
WHEN ENCOUNTERING FLOODED ROADS MAKE THE SMART CHOICE...TURN 
AROUND...DONT DROWN.

TO REPORT FLOODING...HAVE THE NEAREST LAW ENFORCEMENT AGENCY RELAY
YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
OXNARD.

&&

LAT...LON 3431 11797 3454 11793 3456 11779 3436 11774

$$

HALL
128 
WGUS76 KLOX 100309
FFSLOX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE OXNARD CA
809 PM PDT SUN SEP 9 2012

CAC037-100315-
/O.EXP.KLOX.FF.W.0002.000000T0000Z-120910T0315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LOS ANGELES CA-
809 PM PDT SUN SEP 9 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 815 PM PDT FOR EAST 
CENTRAL LOS ANGELES COUNTY...

FLOODING CONTINUES TO RECEDE ACROSS THE ANTELOPE VALLEY AND THE 
NORTH FACING SLOPES OF THE SAN GABRIEL MOUNTAINS. SOME DRAINAGES AND 
WASHES MAY STILL BE SWOLLEN FROM THE RECENT HEAVY RAINFALL EARLIER 
THIS EVENING.

LAT...LON 3431 11797 3454 11793 3456 11779 3436 11774

$$

HALL

The office that day

Everything else NWS Los Angeles, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 9, 6:40 PM PDTAreal Flood AdvisoryLOX93 min
Sep 10, 3:23 AM PDTFlash Flood WatchLOX16 hr
Sep 10, 2:15 PM PDTAreal Flood AdvisoryLOX3 hr
Sep 10, 2:38 PM PDTFlash Flood WarningLOXVentura3 hr
Sep 10, 3:40 PM PDTFlash Flood WarningLOXLos Angeles3 hr
Sep 10, 3:49 PM PDTSevere Thunderstorm WarningLOXLos Angeles26 min
Sep 10, 4:11 PM PDTSevere Thunderstorm WarningLOXLos Angeles64 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.