Winter Storm and High Wind in California, December 1 to 6, 2011

Name: Winter Storm and High Wind in California, December 1 to 6, 2011
Start: 2011-12-01T00:00
End: 2011-12-06T00:00
Location: California

December 1 to 6, 2011 · NWS SGX · 4 events in 3 counties and zones

Where it happened

Every event with a place to put it; 4 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
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $769,000
Crop damage: None recorded
Events: 4

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.

These events were the result of a large upper-level closed low over northern Baja, Mexico and featured four Santa Ana events, the strongest of which occurred in Orange County and southwest San Bernardino County with wind gusts 45 to 65+ mph and reported damage on December 1. These winds were strong enough to overturn several trucks, down power lines, reduce visibilities in dust and topple hundreds of large trees in Rancho Cucamonga (near Fontana, San Bernardino and Ontario), near the Cajon Pass along I-15. Rancho Cucamonga was declared a state of emergency by the State of California for the nearly 500 trees damaged. Overall, approximately 400 tons of debris was mitigated in the Rancho Cucamonga area.This area also suffered damage to the electrical infrastructure leaving many without power. As far as snow goes, 15 to 20 inches occurred in the San Bernardino County Mountains near Big Bear and Onyx Peak December 1 to 2, while only a dusting occurred in those mountains west of I-15. Much drier air moved into San Diego County on Saturday December 3, when the Santa Ana mountains and foothills had another surge of Santa Ana/offshore winds with gusts to near 60 mph and very low relative humidity. The final period of winds developed behind another system passing to our east on Monday, bringing wind gusts to 50 to 65 mph Monday night and Tuesday morning in the San Diego County mountains, and very low humidity.

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 Nov 30, 9:30 PM PST, 2 hours 30 minutes earlier.

Area forecast discussion, Nov 30, 9:30 PM PST, 2 hours 30 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 PM PST WED NOV 30 2011

.SYNOPSIS...
A LOW PRESSURE SYSTEM DROPPING SOUTH INTO THE REGION TONIGHT THROUGH
FRIDAY. THIS STRONG AND COLD SYSTEM WILL BRING STRONG
NORTH-NORTHEAST WINDS...MUCH COLDER WEATHER...AND A CHANCE OF RAIN
AND SNOW SHOWERS THURSDAY AND FRIDAY. A SLIGHT CHANCE OF
THUNDERSTORMS WILL BE POSSIBLE AS WELL. COLD...UNSETTLED WEATHER
LINGERS INTO THE WEEKEND. FAIR WITH LOCALLY GUSTY WINDS EARLY NEXT
WEEK UNDER DRY NORTHERLY FLOW ALOFT.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

AN UPPER LEVEL LOW CURRENTLY CENTERED OVER NEVADA WAS DIGGING
SOUTHWEST INTO CALIFORNIA THIS EVENING. A JET STREAK ROUNDING THE
BASE OF THIS LOW HAS NOSED INTO SOUTHERN CA...GENERATING STRONG
GUSTY WINDS IN LOS ANGELES COUNTY AND POINTS NORTH AND WEST...AND
DEEPENING THE MARINE LAYER SIGNIFICANTLY FURTHER SOUTH. MARINE
CLOUDS HAVE PUSHED INTO THE COASTAL SLOPES OF THE MOUNTAINS AND
DRIZZLE WAS BEING REPORTED IN A FEW LOCATIONS. AN EAST-WEST ORIENTED
SURFACE COLD FRONT IS CURRENTLY POSITIONED IN NORTHERN SAN
BERNARDINO COUNTY AND IS PUSHING TOWARDS THE SOUTH. AS THIS FRONT
PASSES THROUGH OVERNIGHT...EXPECT STRONG GUSTY NORTH-NORTHEAST WINDS
TO DEVELOP AND COLDER AIR TO MOVE INTO THE AREA.

WINDS REMAIN ON TRACK FOR THE NORTHERN AREAS. STRENGTHENING SURFACE
PRESSURE GRADIENTS AND MODERATE TO STRONG UPPER LEVEL WINDS WILL
GENERATE WINDS OF 25 TO 45 MPH WITH GUSTS 55-65 MPH IN THE SAN
BERNARDINO MOUNTAINS...INLAND EMPIRE...THE SANTA ANA MOUNTAINS...AND
INLAND PORTIONS OF THE ORANGE COUNTY COASTAL AREAS. ISOLATED GUSTS
TO 80 MPH ARE POSSIBLE IN THE FAVORED PASSES AND CANYONS. COASTAL
SECTIONS OF EXTREME SOUTHERN ORANGE COUNTY AND NORTHERN SAN DIEGO
COUNTY BELOW THE SANTA ANA MOUNTAINS MAY HAVE GUSTS AS HIGH AS 45
MPH. THE ONLY REAL CHANGE IS THAT THE UPPER LEVEL WINDS ARE MORE
NORTH VERSUS NORTHEAST. MODELS CONTINUE TO SHOW A SURFACE LOW
FORMING OVER WESTERN ARIZONA TONIGHT...MEANING SURFACE PRESSURE
GRADIENTS WILL REMAIN WEAKLY ONSHORE TO THE EAST THROUGH THURSDAY
EVENING. GIVEN THESE SURFACE GRADIENTS AND UPPER LEVEL WIND
DIRECTION...STRONG EAST WINDS IN THE RIVERSIDE AND SAN DIEGO COUNTY
MOUNTAINS ARE UNLIKELY ON THURSDAY. HOWEVER...GUSTY WINDS ARE STILL
EXPECTED ALONG THE RIDGETOPS...ESPECIALLY IN THE NORTHEASTERN SAN
DIEGO COUNTY/SOUTHERN RIVERSIDE COUNTY MOUNTAINS. WINDS 20-40 MPH
WITH GUSTS TO 60 MPH ARE POSSIBLE IN THESE LOCATIONS. WINDS WILL
WEAKEN SLIGHTLY ON THURSDAY AFTERNOON...THEN TURN MORE NORTHEAST AND
STRENGTHEN AGAIN FRIDAY MORNING. THIS SECOND PEAK WILL BE SLIGHTLY
WEAKER IN THE NORTHERN AREAS...BUT STRONGER THROUGH AND BELOW THE
PASSES AND CANYONS OF THE RIVERSIDE AND SAN DIEGO MOUNTAINS. WINDS
QUICKLY DIMINISH BY FRIDAY AFTERNOON AS THE LOW EXITS THE REGION.

THURSDAY AND FRIDAY WILL BE SIGNIFICANTLY COOLER AS THE LOW MOVES
OVER THE AREA...WITH HIGH TEMPS FALLING TO BETWEEN 10 AND 20 DEGREES
BELOW SEASONAL AVERAGES.  THE PREFERRED SOLUTIONS CONTINUE TO SHOW
SOME MOISTURE WITH THE SYSTEM ALONG...WITH A BAND A PRECIPITATION
DEVELOPING OVER THE EASTERN PORTIONS OF THE DESERTS AND MOUNTAINS.
HAVE LEFT IN SLIGHT CHANCE OF RAIN SHOWERS IN THE INLAND AREAS AND
CHANCE OF SNOW IN THE MOUNTAINS. THERE WILL ALSO BE A SLIGHT CHANCE
OF THUNDERSTORMS ON THURSDAY AND FRIDAY AS WELL...AS 500 MB
TEMPERATURES ARE RANGING BETWEEN -24 AND -26 DEGREES. IF ANY
PRECIPITATION DOES OCCUR...SNOW LEVELS WILL RANGE FROM ABOUT
3000-4000 FEET.  RAINFALL AMOUNTS ARE STILL UNCERTAIN...BUT AT THIS
TIME LOOKS LIKE ANY ACCUMULATION WILL BE LESS THAN ONE-TENTH INCH IN
MOST AREAS. UP TO 1-2 INCHES OF NEW SNOWFALL MAY BE POSSIBLE ON THE
NORTH SLOPES OF THE SAN BERNARDINO MOUNTAINS...WITH LESS THAN ONE
INCH ELSEWHERE.

AS THE LOW MOVES EAST ON SAT...ANOTHER CLOSED LOW DEVELOPS OVER
SOUTHERN CALIFORNIA OR THE DESERT SOUTHWEST.  MODELS ARE COMING INTO
BETTER CONSENSUS RETROGRADING THIS SYSTEM TO THE WEST ON
SATURDAY...BEFORE QUICKLY MOVING IT EAST ON SUNDAY AND MONDAY. 00Z
GFS AND 12Z EC HAVE TRENDED FURTHER EAST WITH THIS SYSTEM...MEANING
DRIER CONDITIONS OVER SOUTHERN CALIFORNIA. GUSTY OFFSHORE WINDS WILL
STRENGTHEN AGAIN OVER THE WEEKEND WITH GUSTS 35 TO 45 MPH IN THE
WINDIEST LOCATIONS. DRIER AND WARMER CONDITIONS WILL DEVELOP FOR THE
FIRST PART OF NEXT WEEK.

&&

.AVIATION...
010500Z...STRATUS...WITH BASES MOSTLY AROUND 3000 FT MSL AND SOME
MOUNTAIN OBSCURATION WILL CONTINUE MAINLY OVER SAN DIEGO COUNTY AND
THE W SLOPES OF THE SAN JACINTO MOUNTAINS THROUGH 06Z THEN ERODE
FROM NORTH TO SOUTH THROUGH 12Z. OTHERWISE...CLOUDS WILL INCREASE
ABOVE FL080 FROM NORTH TO SOUTH OVERNIGHT...WITH ISOLATED/SCATTERED
SHOWERS THU MOSTLY IN THE MTNS. ISOLATED TSTM IS POSSIBLE THU.

WINDS...AREAS OF NORTH WINDS 20-35 KT AT THE SURFACE WITH LOCAL
GUSTS OVER 55 KT WILL OCCUR OVER THE SANTA ANA MTNS...NEAR AND SOUTH
OF THE SAN JACINTO MTNS AND BELOW THE CAJON PASS MAINLY AFTER 06Z
AND CONTINUING THROUGH THU. IN OTHER AREAS...WINDS WILL BE MORE
VARIABLE BUT LOCAL GUSTS OVER 40 KT WILL BE POSSIBLE AT TIMES.
BLOWING DUST WILL LOCALLY REDUCE SFC VIS TO 3-5 MI...MAINLY IN SAN
BERNARDINO COUNTY. LLWS WILL OCCUR AT TIMES. WINDS WILL GRADUALLY
DECREASE THU NIGHT.

&&

.MARINE...
GALE FORCE WINDS FROM THE NORTH WILL BE POSSIBLE LATE TONIGHT
THROUGH AT LEAST EARLY THU EVENING WITH GUSTS TO 40 KNOTS.
PREVAILING WINDS WILL BE 20-30 KNOTS. THIS WILL GENERATE WIND WAVES
OF UP TO 5 FEET. THE GALE WARNING CURRENTLY IS IN EFFECT THROUGH 4
AM FRIDAY BUT MAY NEED TO BE DROPPED THU EVENING.

&&

.FIRE WEATHER...
A COLD AND STRONG UPPER LEVEL LOW WILL DIG SOUTH INTO CALIFORNIA
TONIGHT...BRINGING VERY STRONG AND GUSTY NORTH TO NORTHEAST WINDS TO
SOUTHERN CALIFORNIA THROUGH FRIDAY. NORTH TO NORTHEAST WIND GUSTS UP
TO 65 MPH WILL BE POSSIBLE...WITH LOCAL GUSTS UP TO 80 MPH THROUGH
AND BELOW THE FAVORED CANYONS AND PASSES.  ALTHOUGH HUMIDITIES WILL
BE MARGINAL AT BEST...RANGING BETWEEN 15 TO 30 PERCENT...THESE WINDS
WILL CAUSE SOME FIRE CONCERNS FOR PORTIONS OF THE INLAND EMPIRE AND
ORANGE COUNTY. OVERNIGHT HUMIDITY RECOVERY WILL BE MODERATE...EXCEPT
NEAR THE FOOTHILLS OF THE SAN BERNARDINO...RIVERSIDE...AND SANTA ANA
MOUNTAINS WHERE RECOVERY WILL BE POOR. A RED FLAG WARNING IS NOW IN
EFFECT FOR THE INLAND EMPIRE...THE SANTA ANA MOUNTAINS AND
FOOTHILLS...AND THE ORANGE COUNTY COASTAL AREAS THROUGH FRIDAY
AFTERNOON.

ELSEWHERE...THIS SYSTEM WILL BRING A SLIGHT CHANCE OF SHOWERS AND
LOWER ELEVATION SNOW SHOWERS AS WELL AS A SLIGHT CHANCE OF
THUNDERSTORMS THURSDAY THROUGH FRIDAY. ALTHOUGH PRECIPITATION
AMOUNTS WILL BE LIGHT...THERE IS A CHANCE OF SOME WETTING RAINS WITH
THE STRONGER SHOWERS.  THIS WILL KEEP HUMIDITIES IN NON-CRITICAL
RANGES IN THE MOUNTAINS. WINDS WILL DECREASE ON FRIDAY.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...HIGH WIND WARNING UNTIL 2 PM PST FRIDAY FOR THE ORANGE COUNTY
     COASTAL AREAS...RIVERSIDE COUNTY MOUNTAINS...SAN BERNARDINO
     COUNTY MOUNTAINS...SAN BERNARDINO AND RIVERSIDE COUNTY
     VALLEYS-THE INLAND EMPIRE...SAN DIEGO COUNTY MOUNTAINS...
     SANTA ANA MOUNTAINS AND FOOTHILLS.

     WIND ADVISORY UNTIL 2 PM PST FRIDAY FOR THE SAN DIEGO COUNTY
     COASTAL AREAS...SAN DIEGO COUNTY DESERTS...SAN DIEGO
     COUNTY VALLEYS....APPLE AND LUCERNE VALLEYS...COACHELLA
     VALLEY.

     RED FLAG WARNING UNTIL 3 PM PST FRIDAY FOR THE ORANGE COUNTY
     COASTAL AREAS...SAN BERNARDINO AND RIVERSIDE COUNTY
     VALLEYS-THE INLAND EMPIRE...SANTA ANA MOUNTAINS-INCLUDING
     THE TRABUCO RANGER DISTRICT OF THE CLEVELAND NATIONAL
     FOREST.

PZ...GALE WARNING FROM 1 AM THURSDAY TO 4 AM PST FRIDAY FOR THE
     COASTAL WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER
     AND OUT 30 NM...WATERS FROM SAN MATEO POINT TO THE MEXICAN
     BORDER EXTENDING 30 TO 60 NM OUT INCLUDING SAN CLEMENTE
     ISLAND.

&&

PUBLIC/FIRE...SS
AVIATION/MARINE...MAXWELL

Hazardous weather outlook, Nov 30, 4:00 PM PST, 8 hours before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE SAN DIEGO CA
400 PM PST WED NOV 30 2011

CAZ042-043-048-050-055>058-060>062-PZZ750-775-011230-
ORANGE COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS-
SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE-
SAN DIEGO COUNTY VALLEYS-SAN BERNARDINO COUNTY MOUNTAINS-
RIVERSIDE COUNTY MOUNTAINS-SANTA ANA MOUNTAINS AND FOOTHILLS-
SAN DIEGO COUNTY MOUNTAINS-APPLE AND LUCERNE VALLEYS-
COACHELLA VALLEY-SAN DIEGO COUNTY DESERTS-
COASTAL WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER AND OUT
30 NM-
WATERS FROM SAN MATEO POINT TO THE MEXICAN BORDER EXTENDING 30 TO
60 NM OUT INCLUDING SAN CLEMENTE ISLAND-
400 PM PST WED NOV 30 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EXTREME
SOUTHWESTERN CALIFORNIA.

.DAY ONE...TONIGHT

HIGH WIND WARNING FROM 10 PM TONIGHT TO 2 PM PST FRIDAY FOR
THE ORANGE COUNTY COASTAL AREAS...RIVERSIDE COUNTY
MOUNTAINS...SAN BERNARDINO COUNTY MOUNTAINS...SAN BERNARDINO
AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE...SAN DIEGO
COUNTY MOUNTAINS...SANTA ANA MOUNTAINS AND FOOTHILLS.

WIND ADVISORY FROM 7 PM TO 10 PM THIS EVENING FOR THE ORANGE
COUNTY COASTAL AREAS...RIVERSIDE COUNTY MOUNTAINS...SAN
BERNARDINO COUNTY MOUNTAINS...SAN BERNARDINO AND RIVERSIDE
COUNTY VALLEYS-THE INLAND EMPIRE...SANTA ANA MOUNTAINS AND
FOOTHILLS.

RED FLAG WARNING FROM WEDNESDAY EVENING THROUGH FRIDAY
AFTERNOON FOR THE ORANGE COUNTY COASTAL AREAS...SAN BERNARDINO AND
RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE......SANTA ANA
MOUNTAINS-INCLUDING THE TRABUCO RANGER DISTRICT OF THE CLEVELAND
NATIONAL FOREST.

WIND ADVISORY FROM 10 PM THIS EVENING TO 2 PM PST FRIDAY FOR
THE SAN DIEGO COUNTY COASTAL AREAS...SAN DIEGO COUNTY VALLEYS...SAN
DIEGO COUNTY DESERTS.

WIND ADVISORY FROM 7 PM THIS EVENING TO 2 PM PST FRIDAY FOR
THE APPLE AND LUCERNE VALLEYS...COACHELLA VALLEY.

GALE WARNING FROM 1 AM THURSDAY TO 4 AM FRIDAY FOR ALL SAN DIEGO
COUNTY COASTAL WATERS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

THURSDAY THROUGH SATURDAY...A COLD STORM SYSTEM WILL CONTINUE TO
BRING STRONG GUSTY NORTHEAST WINDS AND A SLIGHT CHANCE OF SHOWERS.
PRECIPITATION COULD BEGIN THURSDAY MORNING. ANY PRECIPITATION IS
EXPECTED TO BE LIGHT...BUT ISOLATED THUNDERSTORMS WILL BE POSSIBLE.
SNOWFALL MAY ACCUMULATE ABOVE 4000 FEET IN THE MOUNTAINS AND
ADJACENT HIGH DESERT SLOPES BY SATURDAY MORNING...POSSIBLY MAKING
TRAVEL DIFFICULT IN SOME AREAS.

.SPOTTER INFORMATION STATEMENT...
SKYWARN WEATHER ACTIVATION IS NOT REQUESTED FOR THIS AREA...HOWEVER
WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS.

SS

The radar

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

Open the radar archive at this moment

Event by event

2 high wind, 1 winter storm, 1 strong wind. Local standard time, as filed.

Winter Storm, San Bernardino County Mountains

When: December 1, 12:00 AM PST to December 2, 7:00 AM PST
Where: San Bernardino County Mountains forecast zone
Property damage: $9,000
Reported by: Trained Spotter
Coordinates: 34.841, -116.178 (the zone’s center; the record gives no point)

Snow began falling in the eastern sections of the San Bernardino County Mountains on the evening of November 30th, reached winter storm criteria sometime Thursday evening, December 1st and ceased later that night near midnight. Big Bear City received a storm total of 16 inches. Nearby Big Bear Lake received 18 inches, with some snow drifts reaching 2 to 3 feet. Onyx Peak received a storm total of 16 inches around 8200 feet.|Power lines were also downed in nearby Crestline on Crest Forest Drive at Scenic Drive.

High Wind, San Bernardino and Riverside County Valleys - the Inland Empire

When: December 1, 2:00 AM PST to December 3, 6:00 PM PST
Where: San Bernardino and Riverside County Valleys - the Inland Empire forecast zone
Measured: 43 kt (49 mph) measured sustained
Property damage: $160,000
Reported by: Public
Coordinates: 34.293, -116.086 (the zone’s center; the record gives no point)

The Palm Avenue Elementary weather station in the city of San Bernardino recorded sustained northeast winds of 49 mph around 0700 PST on the 1st. A max gust of 70 mph was also recorded at that station at 0551 PST. |The Cal State San Bernardino mesonet station reported high winds between 0350 and 0550 PST. During this time, sustained winds of 40 mph were recorded along with gusts of 47 and 53 mph.|Numerous occurrences of wind damage near these stations were reported. An overturned box truck was blocking the slow lane of I-15 near Glen Helen Parkway. Power lines and trees were downed near the city of San Bernardino. Power poles and lines were also down across 3rd Avenue near the Crafton Reservoir in Mentone.

Strong Wind, San Bernardino and Riverside County Valleys - the Inland Empire

When: December 1, 2:00 AM PST to December 2, 6:00 PM PST
Where: San Bernardino and Riverside County Valleys - the Inland Empire forecast zone
Measured: 48 kt (55 mph) measured gust
Property damage: $600,000
Reported by: ASOS
Coordinates: 34.293, -116.086 (the zone’s center; the record gives no point)

The Ontario Airport ASOS measured a wind gust of 55 mph around 0300 PST on the 1st. Visibility was reduced to 3 SM in blowing dust due to the strong wind. |In nearby Rancho Cucamonga, the slow lane of Highway 210 at Day Creek Boulevard was closed to upright a semi truck. Fences and hundreds of trees were downed in that area, some blocking roadways. Another big rig overturned in the center divide of Highway 210 at Beech Avenue, blocking the HOV lane until it could be up-righted.

High Wind, San Diego County Mountains

When: December 5, 9:00 PM PST to December 6, 12:00 AM PST
Where: San Diego County Mountains forecast zone
Measured: 56 kt (64 mph) measured gust
Reported by: Mesonet
Coordinates: 33.028, -116.770 (the zone’s center; the record gives no point)

High winds began at the Boulder Creek SDGE mesonet site around 2100 PST on the 5th and ended around midnight on the 6th. During that time, several gusts over 58 mph were recorded including a peak gust of 65 mph around 2130 PST and another of 62 mph around 2300 PST.

What these are

Winter Storm: A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.
High Wind: Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.
Strong Wind: Non-thunderstorm winds below high wind criteria that nonetheless caused damage or casualties.

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

The same day elsewhere

Every storm in California in 2011 Every state in 2011 This day in weather history Warnings in California, December 2011

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: 356555, 356553, 356554, 356556.