Mountain fog caused a chain-reaction automobile collision.
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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 MTR wrote it up.
Mountain fog caused a chain-reaction automobile collision.
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 Francisco Bay Area, CA wrote its last area forecast discussion before the first event at May 2, 4:07 AM PST, 3 hours 53 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN FRANCISCO BAY AREA CA 507 AM PDT SAT MAY 2 2009 .DISCUSSION...AS OF 3:10 AM PDT SATURDAY...THE WEATHER SYSTEM THAT BROUGHT WIDESPREAD RAINFALL TO THE DISTRICT ON FRIDAY HAS...FOR THE MOST PART...MOVED TO THE EAST. LATEST RADAR IMAGERY SHOWS ALL THE SHOWER ACTIVITY IS NOW WELL TO OUR EAST WITH SURFACE OBSERVATIONS BACKING THAT UP BY NOT INDICATING RAIN FOR THE PAST COUPLE OF HOURS. SATELLITE IMAGERY SHOWS A PLUME OF MOISTURE STILL AIMED AT THE CALIFORNIA COAST...AND AS THE AREA REMAINS UNDER AN UNSETTLED WESTERLY FLOW ALOFT...SHOWER CHANCES ARE NOT OVER FOR THE DISTRICT. LATEST MODEL GUIDANCE BRINGS THE NEXT IMPULSE ACROSS THE COASTAL AREAS BY LATER THIS MORNING WITH RENEWED RAIN CHANCES...ESPECIALLY FROM ABOUT THE BAY AREA NORTHWARD. THIS IS FORECAST TO CONTINUE INTO SUNDAY WITH ANOTHER IMPULSE EXPECTED TO REACH THE AREA BY MIDDAY MONDAY FOR BETTER RAIN CHANCES THROUGH TUESDAY. MEDIUM RANGE MODELS DIFFER ON SOLUTION BEYOND TUESDAY WITH THE LATEST GFS BUILDING AN UPPER RIDGE OVER THE AREA FOR DRYING CONDITIONS FROM WEDNESDAY ON...WHILE THE ECMWF KEEPS A FEW SHOWERS OVER THE AREA INTO EARLY THURSDAY BEFORE BUILDING SAID RIDGE. CURRENT FORECAST REFLECTS THE DRIER SCENARIO WITH WARMING TEMPERATURES INTO THE WEEKEND. && .AVIATION...AS OF 5:07 AM PDT SATURDAY...SOUTHERLY WINDS WILL PREVAIL THIS MORNING ACROSS THE SAN FRANCISCO BAY AREA. HOWEVER...AS THE DEPARTING COLD FRONT CONTINUES TO SLIDE EAST WINDS WILL BECOME MORE SOUTHWESTERLY BY AFTERNOON. HIGH MVFR CIGS WILL HANG AROUND TILL LATE MORNING WITH A FEW STRAY SHOWERS AROUND THE AREA. .MONTEREY BAY AREA TERMINALS...HIGH CLOUDS ARE PASSING OVER THE MONTEREY BAY AREA THIS MORNING. EXPECT VFR TO PREVAIL TODAY WITH A FEW SHOWERS POPPING UP AROUND THE AREA THIS AFTERNOON. MVFR CIGS WILL DEVELOP TOWARDS MIDNIGHT. && .MTR WATCHES/WARNINGS/ADVISORIES...NONE. && PUBLIC FORECAST: SSA AVIATION/MARINE FORECAST: LARRY NWS ON THE WEB AT WEATHER.GOV/SANFRANCISCO
The national radar mosaic for the moment the first event began.
1 dense fog. Local standard time, as filed.
Dense fog along with a slippery road surface caused eight traffic collisions along highway 17 in the Santa Cruz county mountains. No major injures were reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2009Every state in 2009This day in weather historyWarnings in California, May 2009
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: 172321.