Flash Flood in California, July 7, 2001

Name: Flash Flood in California, July 7, 2001
Start: 2001-07-07T18:47
End: 2001-07-07T18:47
Location: California

July 7, 2001 · NWS SGX · 1 event in 1 county or zone

A thunderstorm dropped over an inch of rain on Sugar Loaf at the 7000 foot elevation and then moved down the north slope. The ground was already saturated from earlier rains during the day.

Where it happened

Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. 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
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The toll

Deaths: 0
Injuries: 0
Property damage: $20,000
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 SGX wrote it up.

A thunderstorm dropped over an inch of rain on Sugar Loaf at the 7000 foot elevation and then moved down the north slope. The ground was already saturated from earlier rains during the day. The combined effect produced another flash flood on the desert floor across Highway 247 near Pony Road.

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 San Diego, CA wrote its last area forecast discussion before the first event at Jul 7, 1:30 PM PST, 5 hours 17 minutes earlier.

Area forecast discussion, Jul 7, 1:30 PM PST, 5 hours 17 minutes before

EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
230 PM PDT SAT JUL 7 2001

                             ...SYNOPSIS...

THUNDERSTORMS WITH HEAVY RAIN ARE EXPECTED AGAIN OVER THE MOUNTAINS AND
DESERTS INTO THIS EVENING...AND A FLASH FLOOD WATCH IS IN EFFECT UNTIL
900 PM. THERE COULD ALSO BE AN ISOLATED SHOWERS OR THUNDERSTORM IN THE
INLAND VALLEYS INTO THIS EVENING. DRIER SOUTHWEST FLOW ALOFT WILL BRING
A DECREASING CHANCE OF MOUNTAIN AND DESERT THUNDERSTORMS EARLY NEXT
WEEK. A SHALLOW MARINE LAYER WILL CAUSE AREAS OF NIGHT AND MORNING
COASTAL LOW CLOUDS AND FOG...OTHERWISE FAIR.

                             ...DISCUSSION...

LOTS OF MID AND HI LEVEL DEBRIS CLOUDS AROUND THIS AM AND AREAS OF LOW
CLOUDS/FOG NEAR COAST. 12Z NKX SOUNDING NOT QUITE AS WET AS 24 HOURS
PREVIOUS BUT STILL SHOWED MOIST LAYER FROM ABOUT 770 MB TO 500 MB WITH
SLY WINDS THROUGH COLUMN. ONSHORE GRADIENTS WITH ABOUT 4 MB SAN-IPL.
THUNDERSTORMS DEVELOPING OVER THE MOUNTAINS AND DRIFTED OVER THE DESERTS
LATE THIS MORNING AND AFTERNOON...MAINLY N.

MAIN FORECAST PROBLEM WILL BE THUNDERSTORMS WITH HEAVY RAIN AND THE
POTENTIAL FOR FLASH FLOODING INTO THIS EVE. A VORT MAX IS EXPECTED TO
MOVE THROUGH FROM THE SW AND MAY HELP CAUSE A FEW MORE SHOWERS W OF THE
MOUNTAINS. OTHERWISE...THERMAL AND MECHANICAL LIFT OVER MOUNTAIN AND
DESERTS WILL KEEP THEM THE PREFERRED AREAS FOR FLASH FLOODING THIS
AFTERNOON/EVE...ESPECIALLY ON THE S TO SW FACING MOUNTAIN SLOPES. SHOULD
BE INTO NVA LATE TONIGHT FOR DECREASING SHOWERS/THUNDERSTORMS. DRIER SW
FLOW ALOFT DEVELOPS SUNDAY FOR AN END TO THE THREAT OF SHOWERS/
THUNDERSTORMS W OF MOUNTAINS BUT STILL ENOUGH RESIDUAL LOW LEVEL
MOISTURE FOR SOME MENTION IN THE MOUNTAINS/DESERTS WITH EVEN LESS CHANCE
ON MON. GRADUALLY INCREASING HEIGHTS/THICKNESS/850 MB TEMPS AND LESS
CLOUD COVER FOR WARMING IN MOST AREAS. HOWEVER...INCREASING ONSHORE
GRADIENTS TO INTENSIFYING DESERT THERMAL LOW WILL MODERATE MAX TEMPS
NEAR THE COAST. A SHALLOW MARINE LAYER WILL RESULT IN SOME NIGHT/MORNING
COASTAL LOW CLOUDS/FOG.

LONGER RANGE PROGS MAINTAIN DRY SW FLOW ALOFT THROUGH MID WEEK BUT WITH
POSSIBLE WEAK ELY WAVE TUE. UPPER HI SLOWLY BUILDS BACK OVER THE SW
TOWARD THE END OF THE WEEK WITH FLOW ALOFT TURNING MORE SLY AGAIN. WILL
LEAVE IN SOME MOUNTAIN/DESERT THUNDERSTORMS...OTHERWISE FAIR WITH NIGHT/
MORNING COASTAL LOW CLOUDS AND MINOR TEMP CHANGES.

.SAN...FLASH FLOOD WATCH UNTIL 9 PM FOR MOUNTAINS AND DESERTS
       CAZ055-056-058-060-061-062...SEE LAXFFASAN.

ATKIN

In the hours before

Local storm report, Jul 7, 6:40 PM PST, 7 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN DIEGO, CA
740 PM PDT SAT JUL 7 2001

TIME(PDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

1211 PM   11 W LANDERS              CA   FLOOD
07/7/01   SAN BERNARDINO                 WATER 2 FEET DEEP ACROSS
                                          STATE ROUTE 247 ONE MILE
                                          WEST OF PONY ROAD.
                                          NUMEROUS STRANDED
                                          VEHICLES.

1219 PM   1 W CAJON JUNCTION        CA  FLOOD
07/7/01   SAN BERNARDINO                 MUD SLIDE ACROSS LONE PINE
                                          CANYON ROAD JUST SOUTH OF
                                          STATE ROUTE 138.

145 PM    HESPERIA                  CA   FLOOD
07/7/01   SAN BERNARDINO                 WATER 3 FEET DEEP COVERING
                                          ROADWAY. CHP VEHICLE
                                          STRANDED.

145 PM    LUCERNE VALLEY            CA   FLOOD
07/7/01   SAN BERNARDINO                 WATER 2 FEET DEEP COVERING
                                          ROADWAY. SEVERAL VEHICLES
                                          STRANDED.

145 PM    APPLE VALLEY              CA   FLOOD
07/7/01   SAN BERNARDINO                 INTERSTATE 15 AND QUARRY
                                          RD. MAJOR DEBRIS IN
                                          CONSTRUCTION PROJECT
                                          AREA.

218 PM    WRIGHTWOOD                CA   FLOOD
07/7/01   SAN BERNARDINO                 WATER 1.5 FEET DEEP OVER
                                          LONE PINE CANYON ROAD AT
                                          SHEEP CREEK. RAINFALL
                                          OF 3 INCHES IN 90
                                          MINUTES.

240 PM    WRIGHTWOOD                CA   FLOOD
07/7/01   SAN BERNARDINO                 STATE ROUTE 2 FLOODED.
                                          FIST-SIZED ROCKS
                                          ACROSS ROADS.

340 PM    EL DURAGE                 CA   FLOOD
07/7/01   SAN BERNARDINO                 FLASH FLOODING OF ROADS.

348 PM    PHELAN                    CA   FLOOD
07/7/01   SAN BERNARDINO                 CAR PUSHED OFF VALLEY
                                          VISTA ROAD BY WATER.

425 PM    3 W LANDERS               CA   FLOOD
07/7/01   SAN BERNARDINO                 FLOODING ON STATE ROUTE
                                          247.

MARTIN

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, San Bernardino

When: July 7, 6:47 PM PST
Where: San Bernardino County, 18 mi N of Yucca Vly
Property damage: $20,000
Reported by: LAW ENFORCEMENT
Coordinates: 34.841, -116.178 (the zone’s center; the record gives no point)

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 2001 Every state in 2001 This day in weather history Warnings in California, July 2001

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: 5258013.