A powerful late season winter storm brought gusty winds, heavy snow and flash flooding to Southwestern California. 5 inches across coastal and valley areas to 5-10 inches across the foothills and mountains.
Every event with a place to put it. Tap one for its entry below.
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.
The episode as NWS LOX wrote it up.
A powerful late season winter storm brought gusty winds, heavy snow and flash flooding to Southwestern California. Across the area, rainfall amounts were very significant, ranging from 3-7.5 inches across coastal and valley areas to 5-10 inches across the foothills and mountains. This heavy rainfall produced a couple reports of flash flooding. Cold air, associated with the storm, producing low snow levels. Snowfall totals in the mountains ranged between 1 and 4 feet. Gusty south to southwest were reported with some spots experiencing very strong wind gusts in excess of 70 MPH.
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 Los Angeles, CA wrote its last area forecast discussion before the first event at Mar 19, 9:30 PM PST, 3 hours 46 minutes earlier.
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 1030 PM PDT SAT MAR 19 2011 NEW AVIATION DISCUSSION .SYNOPSIS... A STRONG STORM SYSTEM WILL BRING SIGNIFICANT RAIN...MOUNTAIN SNOW AND STRONG WINDS TO THE REGION THROUGH MONDAY. THE HEAVIEST PRECIPITATION WILL OCCUR JUST AHEAD OF THE SYSTEMS COLD FRONT MOVING OVER THE REGION ON SUNDAY AND SUNDAY NIGHT. A BREAK IN THE WET AND UNSETTLED WEATHER PATTERN WILL OCCUR BETWEEN MONDAY AND TUESDAY...BUT A SERIES OF STORM MAY BRING RAIN FOR LATE NEXT WEEK. && .UPDATE... A BAROCLINIC LEAF SIGNATURE IS APPARENT ON THE LATEST VISIBLE AND INFRARED IMAGERY THIS EVENING. INDICATIVE OF THE THE STORM SYSTEM STRENGTHENING AND CYCLOGENESIS TAKING PLACE...THE CURRENT PACKAGE LOOKS IN GOOD SHAPE OVER THE NEXT DAY TO DAY AND ONE-HALF. LATEST NAM-WRF SOLUTIONS HAVE ARRIVED A TAD LIGHTER ON THE PRECIPITATION FOR TONIGHT THROUGH SUNDAY NIGHT...BUT BASED UPON THE LATEST SATELLITE IMAGERY BEST APPROACH APPEARS TO REMAIN CONSISTENT. LATEST AMSU PRECIPITABLE WATER PASSES INDICATE A BROAD TONGUE OF SUB-TROPICAL MOISTURE WITH VALUES GREATER THAN ONE-INCH NOSING INTO THE SYSTEMS SOUTHERN EDGE. LATEST VAPOR IMAGERY ILLUSTRATES THE MOISTURE FLUX INCREASING ALONG THE SYSTEM SOUTH-SIDE. WITH STRONG SOUTHERLY FLOW AND A DECENT WARM AIR ADVECTIVE PATTERN STILL APPARENT IN THE LATEST MODEL SOLUTIONS THIS EVENING...PRECIPITATION OVER THE SAN LUIS OBISPO AND SANTA BARBARA COUNTIES WILL CONTINUE TO PUSH INTO THE VENTURA AND LOS ANGELES COUNTIES AFTER MIDNIGHT. AS FAR AS WIND...WIND HEADLINES MAY BE TWEAKED WITH THE UPCOMING UPDATES MAINLY TO POSSIBLY MAKE THE START TIMES SOONER...BUT ALL WIND HEADLINES WILL REMAIN INTACT FOR NOW. && .PREV DISCUSSION... SHORT TERM...POWERFUL STORM SYSTEM TAKING AIM AT SOUTHERN CALIFORNIA...BRING SIGNIFICANT RAIN...MOUNTAIN SNOW...AND STRONG WINDS TO THE REGION. A STRONG AND COLD UPPER LEVEL LOW PRESSURE SYSTEM IS CURRENTLY CENTERED AROUND 300 NM WEST OF THE OREGON COAST. THIS UPPER LOW IS EXPECTED TO DROP SOUTHWARD AND BECOME CENTERED OFF THE NORTHERN CALIFORNIA COAST ON SUNDAY. THIS SYSTEM IS EXPECTED TO INTERACT WITH A LARGE PLUME OF MOISTURE TO OUR WEST. LEADING EDGE OF WARM FRONTAL PRECIPITATION ALREADY MOVING INTO SAN LUIS OBISPO...SANTA BARBARA...AND WESTERN VENTURA COUNTIES. INCREASING SOUTHERLY FLOW AND A GOOD WARM ADVECTION PATTERN WILL CAUSE RAIN TO SPREAD ACROSS MUCH OF THE REGION TONIGHT...WITH GOOD OROGRAPHIC ENHANCEMENT ON AND BELOW SOUTH FACING SLOPES...ESPECIALLY ACROSS SBA AND WESTERN VTU COUNTIES. MODEL CROSS SECTIONS STILL INDICATING DEEP MOISTURE...STRONG MID LEVEL LIFT...AND VERY STRONG LOW LEVEL SOUTHERLY FLOW ON SUNDAY AND SUNDAY NIGHT IN ADVANCE OF A STRONG COLD FRONT. THIS WILL FURTHER INCREASE THE OROGRAPHIC RAINFALL ENHANCEMENT ACROSS SOUTH FACING SLOPES. THE HEAVIEST RAIN FOR SAN LUIS OBISPO AND SANTA BARBARA COUNTIES IS EXPECTED TO OCCUR ON SUNDAY...SPREADING INTO VENTURA AND LOS ANGELES COUNTIES SUNDAY AFTERNOON INTO SUNDAY NIGHT. AS FAR AS CONVECTIVE ACTIVITY IS CONCERNED...ALREADY SEEING SOME ISOLATED LIGHTNING STRIKES OCCURRING ACROSS THE OUTER COASTAL WATERS THIS AFTERNOON...WHICH SHOULD CONTINUE THROUGH TONIGHT. JET DYNAMICS BECOME QUITE IMPRESSIVE SUNDAY AFTERNOON THROUGH SUNDAY NIGHT...SO HAVE ADDED MENTION OF A SLIGHT CHANCE OF THUNDERSTORMS AS THE FRONT PUSHES THROUGH THE FORECAST AREA. BEHIND THE FRONT...A COLD AND UNSTABLE AIR MASS IN ASSOCIATION WITH THE UPPER LEVEL LOW PRESSURE SYSTEM WILL MAINTAIN A SLIGHT CHANCE OF THUNDERSTORMS THROUGH MANY AREAS UNTIL MONDAY MORNING. TOTAL RAINFALL AMOUNTS EXPECTED TO RANGE FROM 2.50 TO 5 INCHES OF RAIN IN COASTAL AND VALLEY AREAS...AND 5 TO 9 INCHES IN THE FOOTHILLS AND MOUNTAINS BELOW THE SNOW LEVELS...MOST OF WHICH WILL FALL IN AN 18 TO 24 HOUR PERIOD. FLASH FLOOD WATCH IN EFFECT FOR RECENT BURN AREAS...WITH PEAK RAINFALL RATES BETWEEN .50 AND 1.00 INCHES PER HOUR EXPECTED. THE LONG DURATION OF MODERATE TO HEAVY RAIN WILL ALSO LIKELY CAUSE MANY URBAN AND SMALL STREAM FLOODING ISSUES. FOR THE MOUNTAINS...VERY STRONG WINDS...WITH DAMAGING GUSTS OVER 70 MPH ARE EXPECTED. ALSO...SIGNIFICANT SNOW IS EXPECTED AT HIGH ELEVATIONS. THE ONE CONCERN IS THAT SOUTHERLY FLOW COULD LIFT SNOW LEVELS TO RATHER HIGH ELEVATIONS FOR A WHILE SUNDAY...AT LEAST ON COASTAL SLOPES...WHICH COULD REDUCE THE SNOW TOTALS THERE. HOWEVER...AREAS WHERE THE PRECIPITATION STAYS ALL SNOW...1 TO 3 FEET ARE LIKELY. OTHER MAJOR IMPACT WILL BE STRONG WINDS AT LOWER ELEVATIONS. THE 18Z NAM CONTINUES TO ADVERTISE A STRONG SURFACE LOW SPINNING UP OFF THE CENTRAL COAST...WITH A 993 MB CENTER OFF THE MONTEREY COAST BY 06Z TONIGHT. AS A RESULT...A STRONG SOUTHEAST PRESSURE GRADIENT WILL DEVELOP ACROSS OUR COASTAL WATERS OVERNIGHT INTO SUNDAY...WITH STORM WARNINGS POSTED ACROSS THE INNER AND OUTER COASTAL WATERS. HIGH WIND WARNINGS HAVE BEEN POSTED FOR SLO/SBA COUNTIES...AS WELL AS THE ANTELOPE VALLEY AND SANTA MONICA MOUNTAINS...WHERE DAMAGING GUSTS OVER 60 MPH CAN BE EXPECTED. ELSEWHERE...WIND ADVISORIES IN EFFECT FOR THE REMAINDER OF THE AREA. LONG TERM...A FLAT RIDGE WILL BRING SOME DRYING TO THE REGION TUE. ANOTHER FRONTAL SYSTEM WILL BRING A CHANCE OF RAIN TO THE CENTRAL COAST BY LATE TUE NIGHT...AND TO THE REMAINDER OF THE REGION ON WED. THAT SYSTEM DOES NOT LOOK TO BE TOO SIGNIFICANT... WITH THE HEAVIEST RAIN LIKELY N OF PT CONCEPTION. YET ANOTHER ANOTHER FRONTAL SYSTEM MAY BRING RAIN TO THE REGION THU NIGHT AND FRI. TEMPS WILL BE BELOW NORMAL THROUGH THE PERIOD. && .AVIATION... 20/0545Z. RAIN AND STRONG WINDS WILL AFFECT ALL TAF SITES THROUGH 00Z AND WILL THEN DIMINISH SLOWLY. FAIRLY LOW CONFIDENCE IN TAFS AS CIGS AND VIS WILL VARY FREQUENTLY BUT LOW MVFR CONDS WILL DOMINATE. MUCH STRONGER THAN NORMAL SOUTHEAST WINDS THROUGH 00Z WILL CREATE MUCH LOW LEVEL TURBULENCE AND WIND SHEAR. KLAX...LOW CONFIDENCE IN TAF AFT 10Z. RAIN COULD HOLD OFF UNTIL 12Z. AFTER THE RAIN BEGINS CIGS AND VIS WILL VARY FREQUENTLY BUT WILL MOSTLY BE LOW MVFR. THERE WILL BE VERY STRONG XWNDS FROM MID MORNING THROUGH THE AFTERNOON. KBUR...LOW CONFIDENCE IN TAF AFT 10Z. RAIN COULD HOLD OFF UNTIL 12Z. AFTER THE RAIN BEGINS CIGS AND VIS WILL VARY FREQUENTLY BETWEEN IFR AND MVFR CONDS. LGT-MDT TURBC SFC-080 AFT 15Z. && .LOX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING (SEE LAXWSWLOX). HIGH WIND WARNING (SEE LAXNPWLOX). HIGH WIND WATCH (SEE LAXNPWLOX). WIND ADVISORY (SEE LAXNPWLOX). FLOOD WATCH (SEE LAXFFALOX). STORM WARNING (SEE LAXMWWLOX). HIGH SURF ADVISORY (SEE LAXCFWLOX). HIGH RIP CURRENT RISK (SEE LAXSRFLOX). MARINE WEATHER STATEMENT (SEE LAXMWSLOX). && PUBLIC...HALL/GOMBERG AVIATION...ASR SYNOPSIS...HALL WWW.WEATHER.GOV/LOSANGELES
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 429 PM PDT SAT MAR 19 2011 CAZ034>041-044>046-051>054-059-087-088-547-548-201300- SAN LUIS OBISPO COUNTY CENTRAL COAST- SANTA BARBARA COUNTY CENTRAL COAST-SANTA YNEZ VALLEY- SAN LUIS OBISPO COUNTY INTERIOR VALLEYS-CUYAMA VALLEY- SANTA BARBARA COUNTY SOUTH COAST-VENTURA COUNTY COAST- LOS ANGELES COUNTY COAST INCLUDING DOWNTOWN LOS ANGELES- VENTURA COUNTY INTERIOR VALLEYS-VENTURA COUNTY COASTAL VALLEYS- SANTA MONICA MOUNTAINS RECREATIONAL AREA- SAN LUIS OBISPO COUNTY MOUNTAINS- SANTA BARBARA COUNTY MOUNTAINS-VENTURA COUNTY MOUNTAINS- LOS ANGELES COUNTY MOUNTAINS EXCLUDING THE SANTA MONICA RANGE- ANTELOPE VALLEY-CATALINA ISLAND-SANTA CLARITA VALLEY- LOS ANGELES COUNTY SAN FERNANDO VALLEY- LOS ANGELES COUNTY SAN GABRIEL VALLEY- 429 PM PDT SAT MAR 19 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA. .DAY ONE... TODAY AND TONIGHT A STRONG AND POTENT STORM SYSTEM WILL BEGIN TO AFFECT AREAS NORTH OF POINT CONCEPTION TONIGHT BRINGING INCREASING RAINFALL TO THE REGION...STRONG AND DAMAGING WINDS...SIGNIFICANT MOUNTAINS SNOW...HAZARDOUS SEAS...AND HIGH SURF TO THE REGION. MOTORIST AND MARINERS SHOULD EXERCISE CAUTION TONIGHT. THE RAIN WILL LIKELY PRODUCE WIDESPREAD PONDING OF WATER ON AREA ROADWAYS...WITH FLOODING OF LOW LYING AREAS AND INTERSECTIONS. THERE IS A CHANCE THAT RAINFALL RATES COULD BE HIGH ENOUGH TO CAUSE PROBLEMS IN AND BELOW THE RECENT BURN AREAS OF SANTA BARBARA COUNTY. * WINTER STORM WARNING.......SEE WWUS46 KLOX - WSWLOX FOR DETAILS * * HIGH WIND WARNING..........SEE WWUS76 KLOX - NPWLOX FOR DETAILS * * FLOOD WATCH................SEE WGUS66 KLOX - FFALOX FOR DETAILS * * STORM WARNING..............SEE WHUS76 KLOX - MWWLOX FOR DETAILS * * HIGH SURF ADVISORY.........SEE WHUS46 KLOX - CFWLOX FOR DETAILS * * HIGH RIP CURRENT RISK......SEE FZUS56 KLOX - SRFLOX FOR DETAILS * * MARINE WEATHER STATEMENT...SEE FZUS76 KLOX - MWSLOX FOR DETAILS * .DAYS TWO THROUGH SEVEN... SUNDAY THROUGH FRIDAY THE STORM SYSTEM WILL CONTINUE TO BRING PERIODS OF HEAVY RAIN AND MOUNTAIN SNOW TO THE REGION SUNDAY THROUGH EARLY MONDAY. THE RAIN WILL LIKELY PRODUCE WIDESPREAD PONDING OF WATER ON AREA ROADWAYS...WITH FLOODING OF LOW LYING AREAS AND INTERSECTIONS. THERE IS A CHANCE THAT RAINFALL RATES WITH THIS SYSTEM WILL LIKELY EXCEED THE USGS THRESHOLDS FOR FLASH FLOODING AND DEBRIS FLOWS IN AND BELOW THE RECENT BURN AREAS. STRONG AND POTENTIALLY DAMAGING SOUTH WINDS WILL AFFECT MUCH OF THE REGION THROUGH SUNDAY NIGHT. ANOTHER STORM SYSTEM MAY AFFECT THE REGION DURING THE MIDDLE OF NEXT WEEK. * WINTER STORM WARNING.......SEE WWUS46 KLOX - WSWLOX FOR DETAILS * * HIGH WIND WARNING..........SEE WWUS76 KLOX - NPWLOX FOR DETAILS * * HIGH WIND WATCH............SEE WWUS76 KLOX - NPWLOX FOR DETAILS * * FLOOD WATCH................SEE WGUS66 KLOX - FFALOX FOR DETAILS * * WIND ADVISORY..............SEE WWUS76 KLOX - NPWLOX FOR DETAILS * * STORM WARNING..............SEE WHUS76 KLOX - MWWLOX FOR DETAILS * * HIGH SURF ADVISORY.........SEE WHUS46 KLOX - CFWLOX FOR DETAILS * * MARINE WEATHER STATEMENT...SEE FZUS76 KLOX - MWSLOX FOR DETAILS * .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. HALL
The Los Angeles radar (KVTX), 60 km away, was scanning. The volume nearest the first event began at 17:18 UTC.
5 high wind, 3 winter storm, 2 flash flood. Local standard time, as filed.
Strong southerly winds developed across the west coast of Santa Barbara county. A wind tower at Vandenberg Air Force Base reported a southerly wind gusts of 60 MPH at 385 feet elevation.
Strong southerly winds developed across the Santa Ynez Valley. The Santa Ynez Airport reported sustained winds of 40 MPH.
Strong southerly winds developed across the south coast of Santa Barbara county. The RAWS sensor at Las Flores Canyon reported sustained winds of 41 MPH.
A strong mountain wave developed across the Antelope Valley, producing very strong southwesterly winds. The sensor at Valyermo reported wind gusts between 59 and 77 MPH. The RAWS sensor at Lake Palmdale reported wind gusts between 58 and 63 MPH.
California Highway Patrol reported flash flooding across Paradise Road. Several vehicles were stuck in water up to their windshields.
Strong southerly winds developed across the Santa Monica Mountains. A weather spotter in Malibu reported a wind gust of 60 MPH.
Heavy snowfall fell across the mountains of Los Angeles county. Elevations above 4500 feet received between 1 and 4 feet of snow with the highest amounts at the resort level. The heavy snow, combined with gusty southerly winds, produced hazardous winter storm conditions.
Heavy snowfall fell across the mountains of Ventura county. Elevations above 4500 feet received between 1 and 4 feet of snow. The heavy snow, combined with gusty southerly winds, produced hazardous winter storm conditions.
Heavy snowfall fell across the mountains of Santa Barbara county. Elevations above 3500 feet received between 6 and 12 inches of snow. The heavy snow, combined with gusty southerly winds, produced hazardous winter storm conditions.
California Highway Patrol reported flash flooding in the Woodland Hills area. The heavy rain produced a significant mud and debris flow down the road. Five cars were stuck in the mud and one car was swept away. No injuries were reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2011Every state in 2011This day in weather historyWarnings in California, March 2011
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: 288818, 288824, 288821, 288825, 288841, 288826, 288829, 288837, 288838, 288845.