Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 12, NWS San Diego, CA

August 11, 2012San Bernardino County, California

NWS San Diego, CA issued this flash flood warning at Aug 11, 2012, 1:23 PM PDT for San Bernardino County, California. It was in force for 3 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 11, 2012, 1:23 PM PDT (20:23 UTC)
Expired
Aug 11, 2012, 4:15 PM PDT
In force
3 hr
Issued by
NWS San Diego, CA
Area
Storm-based polygon
Flood severity
None

County San Bernardino County, CA

The radar

The Santa Ana Mts radar (KSOX), 72 km from the middle of the area, began a volume at 20:27 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 11, 1:35 PM PDTFLASH FLOODBig Bear City, CASPOTTER HEARD ON HAM RADIO...CAL TRANS AND CHP HAVE CLOSED HIGHWAY 38 AT MILE MARKER 19 DUE TO A STREAM OF WATER RUSHING DOWN THE ROAD WITH EMBEDDED BOULDERS.

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, 8.4 hours before the alert went out and 162 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 2012-08-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 268 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 2012-08-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 21 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
268 J/kg
Mixed-layer CIN
-713 J/kg
Mixed-layer LCL
1560 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
21 m²/s²
0-3 km storm-relative helicity
30 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.

891 
WGUS56 KSGX 112023
FFWSGX
CAC071-112315-
/O.NEW.KSGX.FF.W.0012.120811T2023Z-120811T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE SAN DIEGO CA
123 PM PDT SAT AUG 11 2012

THE NATIONAL WEATHER SERVICE IN SAN DIEGO HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHWESTERN SAN BERNARDINO COUNTY IN SOUTHERN CALIFORNIA...THIS   
  INCLUDES THE CITIES OF HESPERIA...GREEN VALLEY LAKE...AND FOREST   
  FALLS.

* UNTIL 415 PM PDT

* AT 112 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  FLASH FLOODING FROM SEVERAL STORMS OVER THE WARNED AREA.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO RUNNING    
  SPRINGS...LAKE ARROWHEAD...CRESTLINE...BIG BEAR LAKE...BIG BEAR    
  CITY...GREEN VALLEY LAKE...FOREST FALLS AND HESPERIA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DEBRIS FLOWS...INCLUDING MUD AND ROCK SLIDES...ARE POSSIBLE WITH 
THESE STORMS. MUD SLIDES AND ROCK SLIDES CAN POTENTIALLY TRAP AND 
KILL PEOPLE CAUGHT IN THEIR PATH.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

&&

LAT...LON 3409 11718 3426 11745 3434 11744 3442 11737
      3451 11730 3449 11701 3443 11687 3435 11670
      3418 11664 3406 11680 3406 11691 3402 11698

$$

TS
2 follow-up statements
798 
WGUS76 KSGX 112136
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
236 PM PDT SAT AUG 11 2012

CAC071-112315-
/O.CON.KSGX.FF.W.0012.000000T0000Z-120811T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
236 PM PDT SAT AUG 11 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 415 PM PDT FOR
SOUTHWESTERN SAN BERNARDINO COUNTY...

AT 227 PM PDT...TRAINED SPOTTERS REPORTED HEAVY RAIN CAPABLE OF 
PRODUCING FLASH FLOODING OVER THE WARNED AREA.

* LOCATIONS IMPACTED INCLUDE FOREST FALLS. 

* A GAGE AT YUCAIPA RIDGE RECORDED EIGHT TENTHS OF AN INCH OF RAIN  
  WITHIN ONE HALF HOUR. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. MOVE TO HIGHER GROUND.

&&

LAT...LON 3409 11718 3426 11745 3434 11744 3442 11737
      3451 11730 3449 11701 3443 11687 3435 11670
      3418 11664 3406 11680 3406 11691 3402 11698

$$

TS/JJT
838 
WGUS76 KSGX 112310
FFSSGX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
410 PM PDT SAT AUG 11 2012

CAC071-112317-
/O.EXP.KSGX.FF.W.0012.000000T0000Z-120811T2315Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
410 PM PDT SAT AUG 11 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 415 PM PDT FOR SOUTHWESTERN
SAN BERNARDINO COUNTY...INCLUDING THE AREAS OF FOREST FALLS AND BIG 
BEAR CITY.

STORMS IN THE WARNED AREA HAVE DISSIPATED TO THE POINT THAT MAJOR 
FLOODING IS NO LONGER A CONCERN. MINOR RUNOFF AND SOME PONDING ON 
ROADWAYS WILL STILL BE POSSIBLE FOR A FEW HOURS. 

LAT...LON 3409 11718 3426 11745 3434 11744 3442 11737
      3451 11730 3449 11701 3443 11687 3435 11670
      3418 11664 3406 11680 3406 11691 3402 11698

$$

TS/JJT

The office that day

Everything else NWS San Diego, CA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 10, 5:20 PM PDTAreal Flood AdvisorySGXRiverside115 min
Aug 11, 12:00 PM PDTAreal Flood AdvisorySGXSan Bernardino92 min
Aug 11, 12:58 PM PDTAreal Flood AdvisorySGXSan Bernardino2 hr
Aug 11, 1:58 PM PDTAreal Flood AdvisorySGXRiverside, San Bernardino3 hr
Aug 11, 2:03 PM PDTSevere Thunderstorm WarningSGXRiverside27 min
Aug 11, 2:23 PM PDTSevere Thunderstorm WarningSGXRiverside22 min
Aug 11, 2:46 PM PDTSevere Thunderstorm WarningSGXRiverside44 min
Aug 11, 3:05 PM PDTSevere Thunderstorm WarningSGXRiverside, San Diego40 min
Aug 11, 3:22 PM PDTAreal Flood AdvisorySGXSan Bernardino113 min
Aug 11, 3:33 PM PDTSevere Thunderstorm WarningSGXOrange, Riverside42 min
Aug 11, 4:40 PM PDTAreal Flood AdvisorySGXSan Diego3 hr

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.