Flash Flood in California, July 20, 2008

Name: Flash Flood in California, July 20, 2008
Start: 2008-07-20T15:56
End: 2008-07-20T18:45
Location: California

July 20, 2008 · NWS HNX · 1 event in 1 county or zone

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $30,000
Crop damage: None recorded
Events: 1

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS HNX wrote it up.

An upper-level trough approached California on the 20th, bringing yet another surge of monsoonal moisture into the eastern Kern deserts. Outflow boundaries from nocturnal convection over Arizona and northern Mexico generated pre-dawn showers over the China Lake Naval Air Warfare Center and spread clouds across the mountains and the San Joaquin Valley. With the warm, unstable airmass over the region, showers and thunderstorms developed over the Tehachapi Mountains and drifted north into Kern County around sunrise. One storm strengthened into a thunderstorm near Delano, and brought the first measurable rain to Visalia and Fresno since May 27th. 0.01 inch of rain fell at Fresno-Yosemite International Airport, and the Visalia Municipal Airport recorded 0.03 inch of rain from the storm. Widespread mid-level clouds accompanied the monsoonal moisture, and these clouds, in conjunction with a push of low-level marine air through the Sacramento Delta, brought sharp cooling to much of the central and southern San Joaquin Valley on the 20th and 21st. The high temperature for Fresno on July 19th was 102. The next day, Fresno could only reach a high of 89 degrees, a difference of 13 degrees.

One large thunderstorm formed over Barstow during the afternoon of July 20th. As the storm collapsed, strong outflow winds pushed across the Kern County deserts, triggering thunderstorms that produced flash flooding that affected much of Ridgecrest, with fast flowing high water across several city streets. Water rescues were necessary for several people in Ridgecrest due to the flood waters.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Hanford, CA wrote its last area forecast discussion before the first event at Jul 20, 1:08 PM PST, 2 hours 48 minutes earlier.

Area forecast discussion, Jul 20, 1:08 PM PST, 2 hours 48 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
208 PM PDT SUN JUL 20 2008

.DISCUSSION...KHNX 88D INDICATING A FEW HIGH BASED LIGHT SHOWERS
REMAIN OVER THE NORTHERN MOST PORTIONS OF OUR CWFA.
ELSEWHERE...SKIES HAVE CLEARED OUT FROM THE SOUTH THEN
SUBSEQUENTLY CUMULUS HAS BUILT UP AS THE RESULT OF INSTABILITY
IN A FAIRLY MOIST AIRMASS. 18Z WRF RUN INDICATING HIGH CAPES
REMAINING EAST OF OUR CWFA...BUT THERE REMAINS ENOUGH INSTABILITY
AND MID LEVEL MOISTURE TO KEEP MENTION OF A SLIGHT CHANCE TO LOW
CHANCE OF THUNDERSTORMS ACROSS THE MOUNTAINS AND KERN DESERTS
THROUGH THIS EVENING. TEMPERATURES HAVE BEEN RUNNING WELL BELOW
YDAY AS THE RESULT OF THE INCREASED MID LEVEL CLOUD COVER TODAY
WITH THE MOST PRONOUNCED COOLING IN THE CENTRAL AND SOUTH SAN
JOAQUIN VALLEY WHICH ALSO WAS IMPACTED BY AN INTRUSION OF LOW
LEVEL MARINE AIR OVERNIGHT WHERE TEMPERATURES HAVE BEEN RUNNING
AROUND 10 DEG F BELOW YDAY. SOME RECOVERY IS EXPECTED ON MONDAY AS
RH PROGS INDICATE SKIES CLEARING OUT TONIGHT AND P-GRADS HAVE BEEN
DECREASING TODAY.

WRF/GFS CONTINUE TO INDICATE A DRY UPPER LOW CURRENTLY DEPICTED BY
WV NEAR 37N/127W TO TRACK SLOWLY NORTHEAST TONIGHT AND MONDAY THEN
CROSS NORCAL MONDAY NIGHT. BEFORE THE LOW MOVES INLAND...OUR AREA
WILL STILL BE AFFECTED BY THE SURGE OF TROPICAL MONSOONAL
MOISTURE. 18Z WRF INDICATING CAPES OF 400 TO 800 J/KG ACROSS THE
KERN DESERTS AND 200 TO 400 KG OVER THE MOUNTAINS MONDAY AFTERNOON
WITH LI/S BELOW ZERO. WILL THEREFORE KEEP MENTION OF A SLIGHT
CHANCE OF THUNDERSTORMS FOR THESE AREAS FOR MONDAY AFTERNOON AND
EVENING. AFTER THE LOW PASSES BY TO OUR NORTH...HEIGHTS AND
THICKNESSES LOWER SOME ALLOWING FOR TEMPERATURES TO LOWER BY A FEW
DEG F FROM MONDAY. RH PROGS ARE INDICATING A MUCH DRIER AIRMASS
BUILDING INTO OUR AREAS AS WELL AS THE TROUGH ASSOCIATED WITH THIS
UPPER LOW PUSHES THE MONSOONAL MOISTURE WELL TO THE EAST OF OUR
AREA.

A DRY SOUTHWEST FLOW IS EXPECTED TO PREVAIL OVER CENTRAL CA FOR
THE MIDWEEK PERIOD WITH MEDIUM RANGE MODELS IN GOOD AGREEMENT
INDICATING THE LARGE RIDGE OVER THE SOUTH CENTRAL CONUS
RETROGRADING WESTWARD INTO THE FOUR CORNERS AREA BY THE END OF THE
WEEK. THIS WILL RESULT IN A WARMING TREND ACROSS OUR AREA AS
HEIGHTS AND THICKNESSES RISE...PUSHING TEMPERATURES ABOVE CLIMO.
RH PROGS FROM THE GFS AND ECMWF ARE INDICATING THAT MID/UPPER
MONSOONAL MOISTURE WILL RETURN TO THE SOUTHEASTERN PORTION OF OUR
CWFA BY FRIDAY. HOWEVER....ANOTHER TROUGH IS PROGGED TO PUSH INTO
WESTERN CONUS OVER THE WEEKEND WHICH COULD DEFLECT MOST OF THIS
MOISTURE EAST OF OUR AREA. BECAUSE TIMING UNCERTAINTIES WITH THE
RETURN OF THE MONSOON AND THE TROUGH THAT MAY PUSH IT OUT OF OUR
AREA...WILL KEEP MENTION OF LOW POPS IN THE GRIDS ACROSS THE
MOUNTAINS AND KERN DESERTS FOR FRIDAY THROUGH SUNDAY BUT WILL NOT
MENTION THUNDERSTORMS IN THE FORECAST FOR THIS TIME PERIOD UNTIL
CONFIDENCE IMPROVES.

&&

.AVIATION...ISOLATED MVFR AND IFR IN ISOLATED SHOWERS AND
THUNDERSTORMS IN THE EAST SIDE FOOTHILLS AND ALONG THE CREST OF THE
SIERRA NEVADA RANGE AS WELL AS THE KERN COUNTY MOUNTAINS AND DESERT
THIS AFTERNOON AND AGAIN MONDAY AFTERNOON...OTHERWISE VFR CONDITIONS
WILL CONTINUE ACROSS THE REGION THROUGH 00Z TUESDAY.

&&

.AIR QUALITY ISSUES...
ON MONDAY JULY 21 2008...UNHEALTHY FOR SENSITIVE GROUPS IN KERN
AND TULARE COUNTIES. FURTHER INFORMATION IS AVAILABLE AT
VALLEYAIR.ORG

&&

.HNX WATCHES/WARNINGS/ADVISORIES...NONE.

&&

PUBLIC...DS
AVN/FW...JDB

WEATHER.GOV/HANFORD

Hazardous weather outlook, Jul 20, 4:50 AM PST, 11 hours 6 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
550 AM PDT SUN JUL 20 2008

CAZ095>099-211300-
KERN COUNTY MOUNTAINS-SIERRA NEVADA FROM YOSEMITE TO KINGS CANYON-
TULARE COUNTY MOUNTAINS-INDIAN WELLS VALLEY-
SOUTHEASTERN KERN COUNTY DESERT-
550 AM PDT SUN JUL 20 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE SOUTHERN SIERRA
NEVADA...THE TEHACHAPI MOUNTAINS AND THE KERN COUNTY DESERTS.

.DAY ONE...TODAY AND TONIGHT

A RENEWED SOUTHERLY WIND FLOW MAY BRING A RETURN OF MONSOON TYPE
MOISTURE INTO THE KERN COUNTY DESERTS...THE TEHACHAPI MOUNTAINS
AND SOUTHERN SIERRA NEVADA. THERE WILL BE A SLIGHT CHANCE OF
SHOWERS AND THUNDERSTORMS OVER THE KERN COUNTY MOUNTAINS AND
DESERTS THIS MORNING...SPREADING NORTH OVER THE SOUTHERN SIERRA
NEVADA BY THIS AFTERNOON AND CONTINUING INTO THIS EVENING. LOCALLY
HEAVY RAIN FROM THUNDERSTORMS COULD CAUSE RENEWED CONCERN FOR
FLASH FLOODING IN THOSE AREAS MOST PRONE.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

HERE WILL BE A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS MONDAY
AFTERNOON AND EVENING OVER THE MOUNTAINS OF FRESNO...TULARE AND
KERN COUNTIES AND OVER THE KERN COUNTY DESERTS. LOCALLY HEAVY RAIN
FROM THUNDERSTORMS COULD CAUSE RENEWED CONCERN FOR FLASH FLOODING
IN THOSE AREAS MOST PRONE. OTHERWISE...NO HAZARDOUS WEATHER IS
ANTICIPATED.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION MAY BE NECESSARY FOR THE SOUTHERN
SIERRA NEVADA...THE TEHACHAPI MOUNTAINS AND THE KERN COUNTY
DESERTS.

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT OR
UNUSUAL CONDITIONS TO THE NATIONAL WEATHER SERVICE.

WEATHER.GOV/HANFORD

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Kern

When: July 20, 3:56 PM PST to 6:45 PM PST
Where: Kern County, 4.11 mi NNE of (Nid)naf China Lake to 10.23 mi W of Inyokern Airport
Cause: Heavy Rain / Burn Area
Property damage: $30,000
Reported by: Department of Highways
Coordinates: 35.738, -117.664

California Highway Patrol reported flooding on Highway 14 at Robbers Roost (north of Red Rock Canyon). Kern County Department of Highways reported a water, mud and debris flow on Highway 14. Water was up to a foot deep in spots, and several vehicles were stranded. NWS off-duty employee reported water on Inyokern Road was 12 inches deep in spots with several cars stranded. Garlock Road was covered in extensive debris. Flash flooding and mud and debris flow were reported at the junction of Garlock Road and Red Rock Randsburg Road.

What these are

Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in California in 2008 Every state in 2008 This day in weather history Warnings in California, July 2008

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 129882.