Winter Storm, S Sierra Mtns
- When
- January 20, 12:00 PM PST to January 22, 4:00 AM PST
- Where
- S Sierra Mtns forecast zone
- Reported by
- Park/Forest Service
Winter Storm and Damaging Wind in California, January 20 to 23, 2012
The models began converging on a major change in the weather pattern beginning late in the day on January 19th. A Winter Storm Watch was issued for the Southern Sierra Nevada, and Tioga Pass was closed on the 17th; this was the latest date on record that the Pass had been open until.
Where it happened
Every event with a place to put it. 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
The toll
- Deaths
- 1
- Injuries
- 0
- Property damage
- $5,000
- Crop damage
- None recorded
- Events
- 9
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 HNX wrote it up.
The models began converging on a major change in the weather pattern beginning late in the day on January 19th. A Winter Storm Watch was issued for the Southern Sierra Nevada, and Tioga Pass was closed on the 17th; this was the latest date on record that the Pass had been open until.
A weak upper-level trough moved through the central California interior during the night of January 19th-20th. While the trough brought less rain than the computer models had indicated, it did knock down the ridge that had been in place over the state.|The second trough arrived during the evening of the 20th. From midnight to 4 AM on the 21st, 0.63 inch of rain fell on Fresno, a record-setting end to a 60-day stretch without measurable rain. The total rainfall for Fresno on the 21st was 0.79 inch; the old record rainfall had been 0.52 inch, set in 2010.
Lines of showers with a few embedded thunderstorms moved through the central California interior during the early morning hours of January 21st. These lines of convective activity brought locally heavy rain, gusty winds and a few lightning strikes. Scattered thunderstorms continued through the day, producing pea-size hail and a funnel cloud. Tree limbs were blown down by the winds, with downed limbs reported near Lake Isabella and in Yosemite National Park. One large tree limb in the Park fell on a tent cabin, resulting in the death of the occupant.
The third, and final, trough reached central California on the 23rd. This system also brought thunderstorms with small hail. A funnel cloud also was observed. In the Southern Sierra Nevada, snowfall totals from the three storms reached 1 feet in the high country.
An upper-level ridge built into California behind the departing storm. With abundant ground moisture, the stable airmass allowed the lower layers of the atmosphere to cool to saturation. Consequently, areas of dense fog developed the central and southern San Joaquin Valley. The next few nights saw less fog, mainly confined to west of Highway 99. Clouds over the region during the night of January 26th-27th kept the San Joaquin Valley mostly fog free. However, an upper-level short-wave passing through California did produce areas of drizzle on the Valley floor. The clouds also kept low temperatures in the central and southern San Joaquin Valley unseasonably warm. Both Bakersfield and Fresno bottomed out in the lower 50s and tied their record high minimum temperatures for the 27th (51 and 52 degrees, respectively).
Low clouds persisted over the San Joaquin Valley through much of the day on the 27th, and redeveloped over much of the Valley overnight. Areas of dense fog formed around sunrise, mainly in Kern and Merced Counties, and persisted through late morning. Dense fog redeveloped over San Joaquin Valley again during the early morning of January 29th, and persisted through late morning; a few fog patches lingered into the early afternoon hours.
Mid and high clouds moved into California on the 29th ahead of an upper-level trough that weakened the persistent ridge. Due to the clouds, fog development during the morning of January 30th was patchy, with some areas not seeing fog until around sunrise.
An upper-level disturbance approached the central California coast on January 30th, and moved inland during the afternoon. The disturbance had enough dynamics to trigger isolated light rain showers over the central California interior. The showers brought measurable rain to a few locations, including Fresno and NAS Lemoore, and lingered past midnight into the early morning hours of January 31st.
Bakersfield tied for its 10th warmest January on record, and Fresno had its 16th warmest January on record. For the rain season to date, the central and southern San Joaquin Valley had only received between a third and a half of normal.
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 Hanford, CA wrote its last area forecast discussion before the first event at Jan 20, 9:58 AM PST, 2 hours 2 minutes earlier.
Area forecast discussion, Jan 20, 9:58 AM PST, 2 hours 2 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 958 AM PST FRI JAN 20 2012 .SYNOPSIS... WEATHER PATTERN TURNING WET AS A SERIES OF WINTER STORMS WILL IMPACT CENTRAL CALIFORNIA THROUGH EARLY NEXT WEEK. A PACIFIC STORM WILL MOVE THROUGH CENTRAL CALIFORNIA LATE THIS AFTERNOON THROUGH SATURDAY WITH HEAVY SNOWFALL LIKELY OVER THE SOUTHERN SIERRA NEVADA AND MODERATE TO HEAVY RAINFALL POSSIBLE IN THE CENTRAL VALLEY AND SIERRA FOOTHILLS. GUSTY WINDS WILL ALSO AFFECT THE KERN COUNTY MOUNTAIN AND DESERT AREAS SATURDAY IN THE WAKE OF THE STORM. && .DISCUSSION...SATELLITE WATER VAPOR IMAGERY SHOWS THE IMPRESSIVE PACIFIC STORM SYSTEM TAKING AIM ON THE PACNW AND NORCAL. A HEALTHY FETCH OF MOISTURE (~1.5" TPW) ALONG WITH FAVORABLE DYNAMICS AND A ~160KT UPPER JET ALL POINT TO SOME SUBSTANTIAL PRECIPITATION OVER THE CENTRAL CALIFORNIA INTERIOR. THE BULK OF THE ACTIVITY WILL OCCUR DURING THE OVERNIGHT HOURS TONIGHT AND THE WINTER STORM WARNING FOR THE SOUTHERN SIERRA ABOVE 5000 FEET FROM 4 PM TODAY THROUGH 4 PM SATURDAY LOOKS TO BE IN GOOD SHAPE. A TIGHTENING SURFACE PRESSURE GRADIENT ALONG WITH UPPER LEVEL SUPPORT WILL PRODUCE GUSTY WINDS OVER THE KERN COUNTY MOUNTAINS AND DESERT WHERE A WIND ADVISORY IS IN EFFECT FROM 3 AM TO 7 PM SATURDAY. NO UPDATES ARE NEEDED ATTM. && .PREV DISCUSSION... /ISSUED 409 AM PST FRI JAN 20 2012/ DISCUSSION... VERY BUSY NIGHT AS WE ARE FINE TUNING THE FORECAST FOR THE STRONG SYSTEM EXPECTED TO HIT THE CENTRAL CA INTERIOR TONIGHT AND CONTINUE THROUGH SATURDAY. QPF AMOUNTS ARE VERY IMPRESSIVE WITH THE SYSTEM AS A LONG FETCH OF A STRONG 130+ KT UPPER JET WILL PILE UP THE MOISTURE OVER THE REGION. PWAT VALUES ARE 1.25 INCHES IN ASSOCIATION WITH THE FRONT. THE WARM OCCLUSION FRONT IS EXPECTED TO MOVE INTO THE NRN PORTION OF THE CWA BY 2000 PST TONIGHT AND THE HEAVIEST PRECIPITATION IS EXPECTED OVERNIGHT TONIGHT AND GRADUALLY TAPER OFF BY DAYBREAK AS THE FRONT MOVES THROUGH. PLENTY OF COLD AIR BEHIND THE SYSTEM WILL PROVIDE INSTABILITY SHOWERS TO CONTINUE MOST OF THE DAY ON SATURDAY AND TAPER OFF BY SATURDAY AFTERNOON. WINDS ARE EXPECTED TO KICK UP OVER THE KERN COUNTY MOUNTAINS AND DESERT REGIONS ESPECIALLY BEHIND THE FRONT AS THE COLD AIR USHERS IN STRONGER UPPER LEVEL WINDS IN ASSOCIATION WITH A STRONG UPPER JET. THERE WILL BE A BREAK ON SUNDAY BEFORE ANOTHER SYSTEM MOVES INTO THE REGION LATER SUNDAY AFTERNOON. THIS SYSTEM WILL BE A COLD SYSTEM AND SNOW LEVELS WILL POSSIBLY DROP TO AROUND 4000 FEET IN THE SIERRA. QPF AMOUNTS ATTM ARE ADVERTISING ANOTHER FOOT OF SNOW POSSIBLE WITH THIS SYSTEM. THE ECM IS WETTER THAN THE GFS AND ALSO IS MORE DYNAMIC. ONCE THE SYSTEM MOVES THROUGH BY MONDAY AFTERNOON...WE WILL SEE AN UPPER RIDGE BUILD IN OVER THE AREA AND CONTINUE THROUGH THE END OF NEXT WEEK. THIS PATTERN WILL PROVIDE BEAUTIFUL CONDITIONS ACROSS THE SIERRA AND THE KERN COUNTY DESERT REGIONS...HOWEVER IT WILL ONLY MEAN FOGGY AND COOL CONDITIONS FOR THE SJV. WE ARE EXPECTING DENSE FOG TO DEVELOP IN THE SJV WED THROUGH FRIDAY AND WITH THE FRESH RAINFALL IT WILL BE HARD TO BURN OFF IN SOME FOG PRONE LOCALES. CONFIDENCE IS HIGH WITH THE SYSTEM TONIGHT AND SATURDAY AND IS DECREASING WITH THE SUNDAY NIGHT AND MONDAY SYSTEM DUE TO THE INCONSISTENCIES WITH THE GFS AND ECMWF. && .AVIATION... IN THE SOUTHERN SIERRA...WIDESPREAD MTN OBSCURATION IFR ABOVE 6000 FEET MSL. CONDITIONS LOWERING 3000 TO 4000 FEET MSL BY 22Z FRIDAY AND CONTINUING THROUGH 18Z SATURDAY. ELSEWHERE ACROSS THE CENTRAL CA INTERIOR...MVFR IN HAZE AND LIGHT RAIN WITH POSSIBLE IFR CONDITIONS IN HEAVIER SHOWERS AFTER 06Z SATURDAY. FOR THE KERN COUNTY MTNS AND DESERTS...MOSTLY VFR CONDITIONS CHANGING TO MVFR WITH LOCAL MTN OBSCURATION IFR AFTER 06Z SATURDAY. LOCALLY STRONG WINDS WITH GUSTS TO 45KTS AFTER 12Z SATURDAY. && .AIR QUALITY ISSUES... ON FRIDAY JANUARY 20 2012... FIREPLACE/WOOD STOVE BURNING IS PROHIBITED IN FRESNO... KERN... KINGS... MADERA AND TULARE COUNTIES. FURTHER INFORMATION IS AVAILABLE AT VALLEYAIR.ORG && .HNX WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING FROM 4 PM THIS AFTERNOON TO 4 PM PST SATURDAY ABOVE 5000 FEET FOR THE CAZ096-097. WIND ADVISORY FROM 3 AM TO 7 PM PST SATURDAY CAZ095-098-099. && PUBLIC...DCH/JDB AVN/FW...MOLINA SYNOPSIS...JEB WEATHER.GOV/HANFORD
Hazardous weather outlook, Jan 20, 4:43 AM PST, 7 hours 17 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA 443 AM PST FRI JAN 20 2012 CAZ096-097-211245- SIERRA NEVADA FROM YOSEMITE TO KINGS CANYON- TULARE COUNTY MOUNTAINS- 443 AM PST FRI JAN 20 2012 ...HEAVY SNOW... THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE HIGHER ELEVATIONS OF THE SOUTHERN SIERRA NEVADA. .DAY ONE...TODAY AND TONIGHT A PACIFIC WEATHER DISTURBANCE MAY BRING SIGNIFICANT SNOW TO THE SOUTHERN SIERRA...BEGINNING TONIGHT. PLEASE SEE SFOWSWHNX FOR DETAILS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY A PACIFIC WEATHER DISTURBANCE MAY BRING SIGNIFICANT SNOW TO THE SOUTHERN SIERRA...CONTINUING ON SATURDAY. PLEASE SEE SFOWSWHNX FOR DETAILS. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION IS NOT ANTICIPATED. WEATHER SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT OR UNUSUAL CONDITIONS TO THE NATIONAL WEATHER SERVICE. CAZ095-098-099-211245- KERN COUNTY MOUNTAINS-INDIAN WELLS VALLEY- SOUTHEASTERN KERN COUNTY DESERT- 443 AM PST FRI JAN 20 2012 ...GUSTY WINDS... THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE KERN COUNTY MOUNTAINS AND DESERTS. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY A PACIFIC WEATHER DISTURBANCE MAY BRING GUSTY WINDS TO THE AREA. PLEASE SEE SFONPWHNX FOR DETAILS. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION IS NOT ANTICIPATED. WEATHER SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT OR UNUSUAL CONDITIONS TO THE NATIONAL WEATHER SERVICE. CAZ089>094-211245- WEST CENTRAL SAN JOAQUIN VALLEY-EAST CENTRAL SAN JOAQUIN VALLEY- SOUTHWESTERN SAN JOAQUIN VALLEY-SOUTHEASTERN SAN JOAQUIN VALLEY- MARIPOSA MADERA AND FRESNO COUNTY FOOTHILLS- TULARE COUNTY FOOTHILLS- 443 AM PST FRI JAN 20 2012 ...RAIN RETURNS... THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE CENTRAL AND SOUTHERN SAN JOAQUIN VALLEY AND THE ADJACENT FOOTHILLS. .DAY ONE...TODAY AND TONIGHT A PACIFIC WEATHER DISTURBANCE WILL BRING MODERATE TO HEAVY RAIN TO THE AREA. PLEASE SEE SFOSPSHNX FOR DETAILS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY A PACIFIC WEATHER DISTURBANCE WILL BRING MODERATE TO HEAVY RAIN TO THE AREA. PLEASE SEE SFOSPSHNX FOR DETAILS. ANOTHER STORM IS EXPECTED TO IMPACT THE REGION ON SUNDAY NIGHT AND MONDAY. PLEASE SEE SFOSPSHNX FOR DETAILS. .SPOTTER INFORMATION STATEMENT... SKYWARN SPOTTER ACTIVATION IS NOT ANTICIPATED. WEATHER SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT OR UNUSUAL CONDITIONS TO THE NATIONAL WEATHER SERVICE. BARLOW
The radar
The San Joaquin Valley radar (KHNX), 160 km away, was scanning. The volume nearest the first event began at 16:02 UTC.
Event by event
4 winter storm, 2 high wind, 2 funnel cloud, 1 thunderstorm wind. Local standard time, as filed.
Winter Storm, Tulare Cty Mtns
- When
- January 20, 12:00 PM PST to January 22, 4:00 AM PST
- Where
- Tulare Cty Mtns forecast zone
- Reported by
- Park/Forest Service
Thunderstorm Wind, Mariposa
- When
- January 21, 8:00 AM PST
- Where
- Mariposa County, Yosemite Vlg
- Measured
- 40 kt (46 mph) estimated gust
- Deaths
- 1 direct, 0 indirect
- Property damage
- $5,000
- Reported by
- Park/Forest Service
- Coordinates
- 37.750, -119.580
A thunderstorm with heavy rain and lightning moved across Yosemite Valley on the morning of the 21st during a strong winter storm. The thunderstorm briefly generated gusty winds estimated at 40 to 45 mph which caused a tree to fall on a tent. Inside the tent was a park service employee who was killed by the tree fall.
High Wind, Kern Cty Mtns
- When
- January 21, 9:51 AM PST to 7:00 PM PST
- Where
- Kern Cty Mtns forecast zone
- Measured
- 52 kt (60 mph) measured gust
- Reported by
- Mesonet
Funnel Cloud, Fresno
- When
- January 21, 12:35 PM PST
- Where
- Fresno County, 0.88 mi NW of Fig Garden
- Reported by
- Trained Spotter
- Coordinates
- 36.840, -119.830
Funnel Cloud, Fresno
- When
- January 21, 12:36 PM PST
- Where
- Fresno County, 1.66 mi W of Glorietta
- Reported by
- Trained Spotter
- Coordinates
- 36.850, -119.700
High Wind, Se Kern Cty Desert
- When
- January 21, 6:00 PM PST to 7:00 PM PST
- Where
- Se Kern Cty Desert forecast zone
- Measured
- 53 kt (61 mph) measured gust
- Reported by
- Mesonet
Winter Storm, S Sierra Mtns
- When
- January 22, 8:00 PM PST to January 23, 6:00 PM PST
- Where
- S Sierra Mtns forecast zone
- Reported by
- Park/Forest Service
Winter Storm, Tulare Cty Mtns
- When
- January 22, 8:00 PM PST to January 23, 6:00 PM PST
- Where
- Tulare Cty Mtns forecast zone
- Reported by
- Park/Forest Service
The people who died
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Thunderstorm Wind, Mariposa | 2012-01-21 | Male | Camping | Direct |
What these are
- Winter Storm
- A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.
- Thunderstorm Wind
- Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
- High Wind
- Sustained non-thunderstorm winds of 40 mph or more for an hour, or gusts of 58 mph or more.
- Funnel Cloud
- A rotating column of cloud extending from a thunderstorm that did not reach the ground.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Winter Weather in Idaho, January 20 to 21, 2012
- Winter Weather in Iowa, January 20, 2012
- Winter Storm and Winter Weather in Ohio, January 20 to 21, 2012
- Winter Storm and Winter Weather in Ohio, January 20 to 21, 2012
- Winter Weather in Virginia, January 20 to 21, 2012
- Winter Storm and Winter Weather in Indiana, January 20 to 21, 2012
- Heavy Snow in Iowa, January 20, 2012
- Winter Storm in Illinois, January 20, 2012
- Winter Weather in Wisconsin, January 20, 2012
- Winter Weather in Maryland, January 20 to 21, 2012
- Heavy Snow and Winter Weather in Iowa, January 20, 2012
- Winter Weather in South Dakota, January 20, 2012
More
Every storm in California in 2012Every state in 2012This day in weather historyWarnings in California, January 2012
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: 367759, 367760, 367765, 367761, 367757, 367758, 367762, 367763, 367764.