A strong upper low pressure system moved through California on December 27. This system had abundant moisture associated with it as it pulled up a deep fetch of moisture of tropical origin.
Every event with a place to put it; 16 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 HNX wrote it up.
A strong upper low pressure system moved through California on December 27. This system had abundant moisture associated with it as it pulled up a deep fetch of moisture of tropical origin. This system brought widespread moderate to heavy precipitation to the area between the early morning until the early evening of December 27. The heavy rainfall produced a rockslide in Yosemite National Park which resulted in two fatalities. The precipitation tapered off by the early morning of December 28. Much of the higher Sierra Nevada picked up between an inch and a half and three inches of liquid precipitation with the precipitation mainly falling as snow above 7500 feet where many stations picked up between 18 and 30 inches of new snowfall. The snow level briefly lowered to around 6000 feet during the evening of December 27 and some light snowfall was observed between 6000 and 7500 feet. The Sierra foothills generally received between 1 to 2 inches of rain while 0.75 to 1.5 inches of rain fell in the San Joaquin Valley and the Tehachapi Mountains. Several reports of nuisance flooding were reported by law enforcement and on social media. Rain shadowing effects limited precipitation in the Kern County Deserts to a quarter inch or less. This system also brought some strong wind gusts to the mountains as several stations measured gusts exceeding 40 mph and a few low impact stations had brief gusts above 60 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 Hanford, CA wrote its last area forecast discussion before the first event at Dec 27, 3:25 AM PST, 35 minutes earlier.
Area Forecast Discussion National Weather Service Hanford CA 325 AM PST Tue Dec 27 2022 .SYNOPSIS... Multiple storms this week to bring a wet end to 2022. Warmer temperatures will result from this change in pattern as it will dissipate the fog. && .DISCUSSION... The next storm to hit Central California is currently entering the district with light to moderate precipitation falling this morning. Regional Doppler radar showing the heavier showers still over Northern California and tracking southward. Currently, one hour rain rates above measurable amounts to a few one-hundredths remain north to northwest of Yosemite and slowly tracking toward the National Park. By the same token, storm total precipitation accumulation of more than a tenth of an inch are at our foot-steps and ready to overtake the northern portion of the district this morning. The forecast of this next storm has been very consistent as weather models advertised the storm days in advance. Winter storm warnings and flood watches are currently posted and high impacts will affect Central California today. After the storms passage, may see another storm affect the area later in the week. While High Resolution ensemble analysis still shows high confidence in the latest heavy precipitation event, observation analysis will be used in the very short term period. Of which, jet stream level winds at 4 PM PST show Northern and Central California under wind speeds exceeding 50 knots. Satellite-based derived winds were indicating a southward shift of the strong jet winds as speeds of +100 knots were moving into the area. Therefore, will expect strong jet dynamics to enhance the orographic effects as heavy precipitation will soon move into the area. Furthermore, precip-water values have been measured at up to near 1.00 inch. With that much moisture streaming into the region, the potential for heavy precipitation remains high and will warrant the high impacts statements in place for Central California. Upper air observations, along with snow-level radars, were showing the freezing level up close to 10,000 feet. Wet-bulb values of 8,500-8,000 feet will place snow closer to the wet-bulb height and near the expected elevation. While snow levels will remain high, the passage of the surface cold front will help lower snow levels and reducing the threat of flooding. High Resolution ensemble analysis show the disturbance and associated cold front moving pass the region this evening. Precipitation analysis show lingering showers a few hours after sunset before precipitation diminishes overnight. Ensemble Cluster Analysis maintaining a good signal toward the continuation of the unsettled pattern. While ridging over the West will provide the area with a brief rest, additional disturbances will enter the region before the end of the week. Will keep the possibility of precipitation going through at least next Saturday. While clouds will continue to exist over the region, fog will hopefully remain suppressed as the region receives beneficial rain and snow, yet heavy at times. Will still expect the second wave of storms to diminish by next Monday. && .AVIATION... VFR with areas of MVFR conditions will be prevalent for the next 24 hours due to precipitation starting at around 12Z today. IFR and Mountain obscuration conditions may be possible in heavier showers between 20Z today and 02Z Wednesday. && .AIR QUALITY ISSUES... On Tuesday December 27 2022, Unhealthy for Sensitive Groups in Kern County. Fireplace/Wood Stove Burning Status is: No Burning For All in Kern County. No Burning Unless Registered in Fresno and Madera Counties. Burning Discouraged in Kings, Merced, and Tulare Counties, and Kern (Greater Frazier Park Area) and Sequoia National Park and Forest. && .CERTAINTY... The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is medium. Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.html for additional information and/or to provide feedback. && .HNX WATCHES/WARNINGS/ADVISORIES... Flood Watch through this evening for CAZ317-318-324. Winter Storm Warning until 10 AM PST Wednesday for CAZ323- 326>330. && Public/Aviation/Fire Wx...Molina IDSS/PIO/Social Media.....JEB weather.gov/hanford
The national radar mosaic for the moment the first event began.
11 heavy snow, 11 flood, 5 high wind, 1 debris flow. Local standard time, as filed.
The Tenaya Lake SNOTEL (8150 feet) picked up an estimated 18 inches of new snowfall.
The Green Mountain SNOTEL (7900 feet) picked up an estimated 26 inches of new snowfall.
The Devil's Postpile SNOTEL (8004 feet) picked up an estimated 24 inches of new snowfall.
The Kaiser Point SNOTEL (9131 feet) picked up an estimated 24 inches of new snowfall.
The West Woodchuck Meadow SNOTEL (9209 feet) picked up an estimated 23 inches of new snowfall.
The Upper Burnt Corral SNOTEL (9700 feet) picked up an estimated 25 inches of new snowfall.
The Blackcap Basin SNOTEL (10300 feet) picked up an estimated 23 inches of new snowfall.
The Volcanic Knob SNOTEL (10050 feet) picked up an estimated 28 inches of new snowfall.
The Charlotte Lake SNOTEL (11961 feet) picked up an estimated 28 inches of new snowfall.
The Crabtree Meadow SNOTEL (10700 feet) picked up an estimated 23 inches of new snowfall.
The Upper Tyndall Creek SNOTEL (11443 feet) picked up an estimated 23 inches of new snowfall.
The PG&E station at Yosemite Pilot Peak measured a peak wind gust of 59 mph.
California Highway Patrol reported rocks on the road blocking east bound lanes of Huntington Lake Road.
The Walker Pass RAWS measured a peak wind gust of 63 mph.
The Bird Springs Pass RAWS measured a peak wind gust of 77 mph.
The Bear Peak RAWS measured a peak wind gust of 70 mph.
Yosemite National Park employees reported two people were killed by a rockslide near the intersection of SR 140 and Big Oak Flat Road in Yosemite National Park.
California Highway Patrol reported roadway flooding at SR 152 and the Romero Visitor Center.
California Highway Patrol reported a huge boulder on the roadway on SR 168 4E Huntington Lake.
California Highway Patrol reported both sides of the roadway flooded at S. Reed Ave. and E. Annadale Ave.
California Highway Patrol reported SR 140 entrance to Yosemite closed due to a rockfall 3 miles east of the tollbooths.
The Blue Max RAWS measured a peak wind gust of 61 mph.
California Highway Patrol reported roadway flooding at Ave 224 and Ave 216 south of SR 137 west of Tulare.
California Highway Patrol reported flooding on southbound SR 99 as well as on the off ramp of southbound SR 99 to SR 119.
California Highway Patrol reported a small mudslide blocking the southbound lane of Tupman Road north of SR 119.
California Highway Patrol reported flooding on Calloway Dr. underneath the railroad bridge north of Slinker Dr.
California Highway Patrol reported flooding on westbound SR 58 at the intersection of Cottonwood Rd.
California Highway Patrol reported flooding near the intersection of SR 43 and Merced Ave. near Shafter.
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 |
|---|---|---|---|---|---|
| Debris Flow, Mariposa | 2022-12-27 | Unknown | Direct | ||
| Debris Flow, Mariposa | 2022-12-27 | Unknown | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2022Every state in 2022This day in weather historyWarnings in California, December 2022
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: 1061622, 1061623, 1061624, 1061625, 1061626, 1061627, 1061628, 1061630, 1061631, 1061633, 1061635, 1061520, 1061529, 1061527, 1061524, 1061526, 1061849, 1061530, 1061532, 1061533, 1061534, 1061522, 1062349, 1062367, 1062370, 1062371, 1062372, 1062373.