A late season winter-like storm brought fresh snow to the mountains of interior Northern California.
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 STO wrote it up.
A late season winter-like storm brought fresh snow to the mountains of interior Northern California.
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 Sacramento, CA wrote its last area forecast discussion before the first event at Apr 12, 3:30 AM PST, 1 hour 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SACRAMENTO CA 430 AM PDT THU APR 12 2012 .DISCUSSION... BACK EDGE OF PACIFIC FRONTAL BAND NOW APPEARS TO BE ALONG A ROUGHLY REDDING TO SANTA ROSA LINE AND CONTINUING EASTWARD. RAINFALL SO FAR HAS BEEN MAINLY MODERATELY HEAVY WITH SOME CONVECTIVE LINES OF BRIEF HEAVY PRECIP. ALL MODELS SEEM TO BE RUNNING A LITTLE SLOW WITH THIS SYSTEM WITH THE GFS BEING THE FASTEST RUNNING ONLY A FEW HOURS BEHIND ON POSITIONING OF THIS FRONTAL BAND WHICH SHOULD BE PUSHING INTO THE NORTHERN SIERRA BY MID DAY TODAY. THE SURFACE PRESSURE GRADIENT ASSOCIATED WITH THIS FRONT IS TOPPING 9 MB FROM KSAC TO KMFR AND WIND GUSTS IN THE COASTAL RANGE AND NORTHERN SACRAMENTO VALLEY HAVE REACHED UP TO AROUND 40 MPH. IR SATELLITE IMAGERY SHOWS PLENTY OF CONVECTION IN UNSTABLE AIR OFFSHORE CIRCLING THE MAIN LOW NOW CENTERED AROUND 46 NORTH 138 WEST. THIS CONVECTIVE ACTIVITY WILL KEEP SHOWERS GOING ACROSS THE CWA THROUGH THE DAY. A SHORTWAVE TROUGH IS FORECAST TO PIVOT OUT OF THE MAIN LOW AND THROUGH NORCAL THIS AFTERNOON DESTABILIZING THE AIRMASS EVEN MORE. THEREFORE...LOOKS LIKE ANOTHER DAY OF ISOLATED THUNDERSTORMS AND ASSOCIATED WEATHER. NOT SURE IF SEVERE WEATHER IS IN THE CARDS FOR THIS AFTERNOON BUT LIKE YESTERDAY...BEST CHANCES FOR MOST SIGNIFICANT THUNDERSTORM ACTIVITY WOULD BE OVER THE SOUTHERN CWA CLOSEST TO THE LEFT EXIT REGION OF THE JET. SHOULD HAVE NO PROBLEM GETTING ENOUGH SNOW AT THE HIGHER ELEVATIONS TO WARRANT THE WINTER STORM WARNING CURRENTLY IN PLACE ALTHOUGH SNOW AMOUNTS OVER THE COASTAL RANGE WHICH WILL LACK IDEAL OROGRAPHICS WILL LIKELY ONLY REACH MINIMAL CRITERIA. THE SIERRA CASCADE RANGE ON THE OTHER HAND CONTINUES TO HAVE NEARLY IDEAL OROGRAPHICS AND WILL LIKELY PICK UP GREATER THAN A FOOT OF SNOW AT THE 5000 FOOT LEVEL WITH 2 FEET OR MORE AT THE HIGHEST ELEVATIONS BETWEEN NOW AND FRIDAY AFTERNOON. THE MAIN UPPER LOW WILL DROP ACROSS NORTHERN CALIFORNIA ON FRIDAY. GREATEST INSTABILITY WILL BE NEAR THE CENTER OF THE LOW WHICH IS CURRENTLY FORECAST TO TRACK THROUGH THE DELTA AREA FRIDAY AFTERNOON. HAVE KEPT A THREAT OF THUNDERSTORMS IN THIS AREA ON FRIDAY WITH GENERAL SHOWERS ELSEWHERE. CLOUDS AND COLD AIR WILL KEEP DAYTIME HIGHS TODAY AND FRIDAY WELL BELOW NORMAL FOR THIS TIME OF YEAR. UPPER FLOW TURNS TO NORTHERLY FRIDAY NIGHT AND SHOWER ACTIVITY SHOULD END FROM THE NORTH AS UPPER RIDGE PUSHES IN BRINGING INCREASED SUBSIDENCE. SUBSIDENCE AND DECREASED CLOUD COVER WILL BRING WARMER TEMPERATURES SATURDAY BUT WILL STILL SEE HIGHS SEVERAL DEGREES BELOW NORMAL. AS UPPER RIDGE AXIS BUILDS OVER THE COAST ON SUNDAY LOOK FOR EVEN MORE WARMING WITH HIGHS SUNDAY PUSHING UP CLOSE TO NORMAL FOR MID APRIL. .EXTENDED DISCUSSION (MONDAY THROUGH THURSDAY) HIGH PRESSURE RIDGE CONTINUES INTO THE FIRST PART OF NEXT WEEK WITH DRY WEATHER AND SEASONAL TEMPERATURES. VALLEY HIGHS IN THE LOW TO MID 70S FOR MONDAY AND TUESDAY. PRIOR FORECASTS SHOWED THAT TEMPS WOULD BE SLIGHTLY ABOVE NORMAL BUT THE LATEST MODEL RUNS ARE INDICATING THE RIDGE COULD FLATTEN/WEAKEN MONDAY NIGHT INTO TUESDAY. AS THIS OCCURS...ANOTHER LOW PRESSURE STORM IN THE GULF OF ALASKA PUSHES A COLD FRONT TOWARDS THE PAC NW WITH SOME OF THE MOISTURE GLANCING FAR NORCAL ON TUESDAY. HAVE PUT SLIGHT CHANCE OF SHOWERS ACROSS THE MOUNTAINS OF SHASTA COUNTY FOR TUESDAY WITH INCREASING CHANCES OF RAIN/SNOW SPREADING SOUTHWARD ON WED AND THURS AS THE LOW MOVES INLAND. WINDS WILL BE LIGHT DURING THE EXTENDED FORECAST. JBB && .AVIATION... AS OF 3:45 AM LOCAL TIME...COLD FRONTAL BAND OF PRECIPITATION IS CURRENTLY IMPACTING KRDD-KRBL VCNTY. THE BAND IS ORIENTED NNE-SSW WITH MODERATE TO HEAVY SHOWERS EMBEDDED WITHIN AS IT MOVES EASTWARD. ENHANCED SLY WINDS AND GUSTS AHEAD OF AND DURING FRONTAL PASSAGE. GUSTS UP TO 34 KTS WERE OBSERVED AS THE FRONT EDGED TOWARDS KRDD-KRBL AND WINDS ARE NOW INCREASING IN THE SAC METRO AREA WITH THE FRONT JUST TO THE WEST OF SACRAMENTO. MVFR CIGS/VSBYS DOMINANT DURING FRONTAL PASSAGE WITH LCL IFR CONDS DURING HEAVIER SHOWERS. FOR THE REST OF TODAY...SLY WINDS IN SAC VLY SHOULD BE SUSTAINED 10-20 KTS WITH GUSTS UP TO 30 KTS. FOR NRN SAN JOAQUIN VLY...SLY WINDS SUSTAINED 8-18 KTS AND ONLY OCCASIONALLY STRONGER GUSTS. WINDS WILL LIGHTEN AFT 0Z FRI. HEAVIEST RAIN SHOULD OCCUR BTWN NOW AND 18Z FOR TAF SITES AS THIS BAND MOVES THROUGH. ADDITIONAL SCATTERED SHOWERS AND POSSIBLE THUNDERSTORMS DURING THE AFTN WITH A MIX OF VFR/MVFR CONDS. OVER MOUNTAINS...IFR/LIFR CONDS WITH SNOW SHOWERS AND GUSTY WINDS THROUGH THE DAY. && .STO WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING THROUGH 8 PM PDT FRIDAY ABOVE 3500 FEET FOR THE WEST SLOPE NORTHERN SIERRA NEVADA...WESTERN PLUMAS COUNTY/LASSEN PARK. WINTER STORM WARNING UNTIL NOON PDT FRIDAY ABOVE 3500 FEET FOR THE MOUNTAINS SOUTHWESTERN SHASTA COUNTY TO NORTHERN LAKE COUNTY...SHASTA LAKE AREA / NORTHERN SHASTA COUNTY. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SACRAMENTO CA 700 AM PDT WED APR 11 2012 CAZ013>019-063-064-066>069-121400- SHASTA LAKE AREA/NORTHERN SHASTA COUNTY- BURNEY BASIN/EASTERN SHASTA COUNTY-NORTHERN SACRAMENTO VALLEY- CENTRAL SACRAMENTO VALLEY-SOUTHERN SACRAMENTO VALLEY- CARQUINEZ STRAIT AND DELTA-NORTHERN SAN JOAQUIN VALLEY- MOUNTAINS SOUTHWESTERN SHASTA TO NORTHERN LAKE COUNTIES- CLEAR LAKE/SOUTHERN LAKE COUNTY-MOTHERLODE- EAST FOOTHILLS/NORTH SACRAMENTO VALLEY- WESTERN PLUMAS COUNTY/LASSEN PARK-WEST SLOPE NORTHERN SIERRA NEVADA- 700 AM PDT WED APR 11 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR INTERIOR NORTHERN CALIFORNIA. .DAY ONE...TODAY A WEATHER SYSTEM PASSING THROUGH NORCAL TODAY WILL BRING SNOW SHOWERS TO THE MOUNTAINS AND A THREAT OF THUNDERSTORMS THIS AFTERNOON. * WINTER WEATHER ADVISORY....SEE WWUS46 KSTO - WSWSTO FOR DETAILS * .DAYS TWO THROUGH SEVEN... THURSDAY THROUGH TUESDAY ANOTHER WEATHER SYSTEM PASSING THROUGH NORCAL WILL BRING MODERATE TO HEAVY SNOW AT TIMES TO THE MOUNTAINS OF NORTHERN CALIFORNIA THURSDAY THROUGH FRIDAY. GUSTY SOUTH WINDS ARE ALSO FORECAST FOR THE NEXT COUPLE OF DAYS ESPECIALLY ON THURSDAY. * WINTER STORM WATCH.........SEE WWUS46 KSTO - WSWSTO FOR DETAILS * .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS TO THEIR LOCAL NATIONAL WEATHER SERVICE OFFICE. THE LATEST WEATHER INFORMATION IS AVAILABLE ON THE INTERNET AT (LOWER CASE): HTTP://WWW.WRH.NOAA.GOV/STO
2 winter storm. Local standard time, as filed.
Five to ten inches of snow fell at the higher elevations as winds gusted to 35 mph along the west slopes.
Five to twelve inches of snow fell at the higher elevations as winds gusted to 45 mph along the west slopes.
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, April 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: 374194, 374195.