Deep, monsoonal flow continued from earlier in the month. Some minor flooding occurred near Dulzura in San Diego County.
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 SGX wrote it up.
Deep, monsoonal flow continued from earlier in the month. Some minor flooding occurred near Dulzura in San Diego County. Flash flooding occurred in Apple Valley and Victorville (one high water rescue, damage to property and school and multiple road closures), mud and debris on roadways in Alpine, and more flash flooding in Mill Creek at Forest Falls. The Victorville area was hardest hit during these two days.
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 Aug 16, 8:50 AM PST, 2 hours 40 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN DIEGO CA 950 AM PDT THU AUG 16 2012 .SYNOPSIS... SUBTROPICAL MOISTURE WILL CONTINUE TO SPREAD OVER SOUTHERN CALIFORNIA THROUGH THE WEEKEND...AS A RIDGE OF HIGH PRESSURE REMAINS OVER THE DESERT SOUTHWEST. THEREFORE...EXPECT TEMPERATURES TO BE NEAR OR SLIGHTLY ABOVE NORMAL THROUGH THE PERIOD...AS PERIODS OF HIGH CLOUDS MAY MODERATE TEMPERATURES FROM DAY TO DAY. AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER THE MOUNTAINS AND DESERTS...AND MAY SPREAD INTO THE WESTERN VALLEYS AS WELL. A TROUGH MAY BRING SOME COOLER AND DRIER CONDITIONS TOWARDS THE MIDDLE OF NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... WATER VAPOR IMAGERY CONTINUES TO SHOW AN UPPER LEVEL LOW SLOWLY MIGRATING WEST OF 130 WEST THIS MORNING...AS HIGH PRESSURE EXPANDS ACROSS SOUTHERN CALIFORNIA ONCE AGAIN. WATER VAPOR IMAGERY ALSO SHOWS PLENTY OF UPPER LEVEL MOISTURE SPREAD ACROSS THE REGION AS WELL AS A WEAK DISTURBANCE MOVING AROUND THE RIDGE OF HIGH PRESSURE AND ACROSS SOUTHEASTERN CALIFORNIA THIS MORNING...TRIGGERING SCATTERED SHOWERS AND THUNDERSTORMS ACROSS IMPERIAL AND EASTERN RIVERSIDE COUNTIES. RADAR IMAGERY SHOWS A FEW WEAK RETURNS MOVING INTO SAN DIEGO COUNTY...BUT SO FAR...THESE ECHOES DO NOT APPEAR TO BE REACHING THE SURFACE. THE 12Z KNKX SOUNDING SHOWS A VERY MOIST AND UNSTABLE ATMOSPHERE OVER THE REGION...SO THINK THAT THIS DISTURBANCE SHOULD BE ENOUGH TO TRIGGER SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AND DESERTS LATER TODAY...EVEN GIVEN THE AMOUNT OF MID AND HIGH LEVEL CLOUD COVER. ALTHOUGH PRECIPITABLE WATER VALUES ARE OVER 1.7 INCHES...WILL HOLD OFF ON ISSUING A FLASH FLOOD WATCH FOR TODAY...BECAUSE AM SOMEWHAT CONCERNED THAT THE CLOUD COVER MAY LIMIT THE THUNDERSTORM COVERAGE TODAY. THIS CLOUD COVER ALSO KEPT OVERNIGHT TEMPERATURES FROM FALLING BELOW 70 DEGREES ACROSS A GOOD PORTION OF THE AREA LAST NIGHT. FOR THIS REASON...TEMPERATURES AT THIS TIME ARE RUNNING 3 TO 6 DEGREES WARMER THAN THIS TIME YESTERDAY...AND EXPECT TEMPERATURES TO BE SIMILAR TO OR ONLY SLIGHTLY WARMER THAN YESTERDAY. THIS PATTERN WILL REALLY NOT CHANGE OVER THE NEXT SEVERAL DAYS...AS THE RIDGE OF HIGH PRESSURE REMAINS RELATIVELY STATIONARY OVER THE DESERT SOUTHWEST. THEREFORE...EXPECT THE SUBTROPICAL MOISTURE TAP TO CONTINUE...POTENTIALLY ENTRAINING SOME REMNANT MOISTURE FROM TROPICAL DEPRESSION HECTOR. THEREFORE...ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL POSSIBLE EACH AFTERNOON THROUGH THE EARLY EVENING HOURS OVER THE MOUNTAINS AND DESERTS. HOWEVER...GIVEN THE SOUTHEASTERLY TO EASTERLY FLOW ALOFT...BELIEVE THAT THE EASTERN PORTIONS OF THE INLAND VALLEYS MAY SEE SOME ACTIVITY AS WELL...ESPECIALLY FOR FRIDAY AND SATURDAY. THERE MAY ALSO BE LESS HIGH CLOUD COVER THESE DAYS INITIALLY...WHICH WOULD AID IN THE SURFACE HEATING AS WELL. THE EXTENDED MODELS SHOW AN UPPER LEVEL TROUGH OF LOW PRESSURE DIGGING ALONG THE WEST COAST FOR THE FIRST PART OF NEXT WEEK...TRANSITIONING THE UPPER LEVEL FLOW FROM EASTERLY OR SOUTHEASTERLY TO SOUTHWESTERLY. SOME MOISTURE MAY LINGER OVER THE MOUNTAINS AND DESERTS...KEEPING A SLIGHT CHANCE OF SHOWERS OR THUNDERSTORMS POSSIBLE FOR MONDAY AND TUESDAY. HOWEVER...DRIER CONDITIONS SHOULD DEVELOP BY WEDNESDAY. THIS TROUGH MAY ALSO BRING SLIGHTLY COOLER CONDITIONS TO THE REGION AS WELL AS A SLIGHTLY DEEPER MARINE LAYER. && .AVIATION... 161508Z...COAST...PATCHY STRATUS HAS MOSTLY CLEARED OUT OF THE COASTAL AREAS THIS MORNING...MAKING WAY FOR PREVAILING UNRESTRICTED VIS...WITH BKN-SCT CLDS IN THE 15000-25000 FT MSL LAYER...THROUGH 17/0900 UTC. 17/0900-1500 UTC...PATCHY STRATUS POSSIBLE ALONG THE SAN DIEGO COUNTY COAST...WITH BASES 800-1000 FT MSL AND TOPS AROUND 1200-1300 FT MSL. KSAN AND KCRQ MAY SEE BKN-OVC CIGS AT TIMES AND VIS 3-6SM BR. ANY STRATUS THAT FORMS SHOULD CLEAR OUT BY 17/1500 UTC. VALLEYS...PREVAILING UNRESTRICTED VIS...WITH BKN-SCT CLDS IN THE 15000-25000 FT MSL LAYER THROUGH FRIDAY MORNING. ISOLATED THUNDERSTORMS/SHOWERS POSSIBLE IN THE EASTERN VALLEYS 1800-17/0000 UTC. MTNS/DESERTS...POCKETS OF SMOKE ARE POSSIBLE OVER ANZA BORREGO DESERTS/COACHELLA VALLEY NEAR THE SEVERAL FIRES IN THAT AREA...WHICH COULD PRODUCE LOWER VIS AT TIMES. ISOLATED THUNDERSTORMS/SHOWERS WITH EMBEDDED CB WILL BE POSSIBLE 1800-17/0200 UTC. CB TOPS WILL BE AROUND 40000 FT MSL. THUNDERSTORMS/SHOWERS MAY PRODUCE STRONG UP/DOWNDRAFTS AND LOWERED VIS. OTHERWISE...PREVAILING UNRESTRICTED VIS WITH BKN-SCT CLDS IN THE 10000-25000 FT MSL LAYER EXPECTED THROUGH FRIDAY MORNING. && .MARINE... A 3-4 FOOT/18 SEC SOUTHERLY SWELL GENERATED FROM WHAT CURRENTLY IS TROPICAL DEPRESSION HECTOR WILL ARRIVE TO OUR COASTAL WATERS TOMORROW MORNING...AND RESULT IN A BOOST IN SURF HEIGHTS THROUGH MOST OF THE WEEKEND. SURF OF 3-5 FEET WITH ISOLATED SETS TO 6 FEET IS EXPECTED FOR THE SOUTH FACING SHORES OF ORANGE COUNTY. SURF IN SAN DIEGO COUNTY WILL REMAIN AT ONLY 2-3 FT...EXCEPT FOR THE MORE SOUTHERLY FACING BEACHES WHERE SETS TO 5 FEET ARE POSSIBLE. ANY PERSONS SWIMMING IN THE WATER IS RECOMMENDED TO SWIM NEAR A LIFEGUARD AT ALL TIMES. && .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC...PALMER AVIATION/MARINE...HARRISON
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE SAN DIEGO CA 540 AM PDT THU AUG 16 2012 CAZ042-043-048-050-055>058-060>062-PZZ750-775-171030- 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- 540 AM PDT THU AUG 16 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EXTREME SOUTHWESTERN CALIFORNIA. .DAY ONE...TODAY AND TONIGHT. THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AND DESERTS THROUGH EARLY EVENING. THE FLASH FLOOD POTENTIAL INDEX IS MODERATE...ISOLATED FLASH FLOODING IS POSSIBLE. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THERE IS A SLIGHT CHANCE OF SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS AND DESERTS FRIDAY AFTERNOON AND EVENING. THE FLASH FLOOD POTENTIAL INDEX IS MODERATE...ISOLATED FLASH FLOODING IS POSSIBLE. FOR SATURDAY THROUGH TUESDAY...THUNDERSTORMS AND SHOWERS ARE POSSIBLE OVER THE MOUNTAINS AND DESERTS EACH AFTERNOON AND EARLY EVENING. .SPOTTER INFORMATION STATEMENT... SKYWARN WEATHER ACTIVATION IS NOT REQUESTED FOR THIS AREA... HOWEVER WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS. PG
The national radar mosaic for the moment the first event began.
3 flash flood, 1 thunderstorm wind, 1 debris flow, 1 flood. Local standard time, as filed.
CHP is reporting a mud, dirt and rock slide along Deerhorn Valley Road. They also reported that heavy rain was causing flooding near Otay Lakes Road and that the bridge near the fire station was about to be washed out. No word was received if it actually did wash out.
Rob Balfour reported strong winds at the Buck Fire base camp at Diamond Lake, with estimated max gusts of 60 mph. The winds destroyed two large tents, several camping tents and some awnings. A few port-a-potties overturned as well.
Several mudslides were reported in the Forest Falls area, the first of which was reported at Valley of the Falls Drive and Lilac Road with mud over the roadway. Numerous side streets are also covered in mud, with up to 5 feet of mud and debris in Mill Creek. No rescues or injuries but people are stuck in their cars and houses because of mud in the roads. The Yucaipa Ridge rain gauge (owned San Bernardino County Flood Control and just south of Forest Falls) reported massive rainfall of 5.36 inches in 1 hour and 45 minutes, between 1200 and 1347 PST. A short time later, the Mill Creek tributary, Rattlesnake Creek, was reported at bank-full. A spotter sent in a video of the water and debris flow in the normally dry creek, which was up to the bridge at one time.
Spotter SBD625 reported debris flows through canyons near Hesperia about one foot deep and 10 feet wide.
Spotter SDG437 reported mud and debris on the road at Japatul Valley and Lyons Roads as a result of a stationary and heavy thunderstorm over the area.
Spotter 625 reported 6 to 8 inches of water on the roadway near Bear Valley and Amethyst with the roadway completely covered with debris and water. There was also water flowing rapidly across the roadway approximately 1 to 2 feet deep, not allowing cars to pass. The same spotter also reported that the roadway at Corwin and Waalew Roads was covered with debris but still passable. The debris consisted of mostly dirt and rocks with an estimated 5 inches of water flow. A driver was stuck in widespread urban flooding at Topaz and Luna Roads in Victorville. Water was flowing very strong along Arrowhead Road at the Victorville Golf Course, resulting in a water rescue. Another spotter reported 2 to 4 inches of water over the intersection of Highway 395 and Highway 18, containing a lot of debris and stranding a few cars.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2012Every state in 2012This day in weather historyWarnings in California, August 2012
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: 407754, 407753, 409832, 407757, 409833, 409834.