An atmospheric river brought heavy rain and snow to parts of California on 31 December 2022. At least 2 people have died, dozens rescued and hundreds evacuated. More severe weather is forecast for the coming days.
The storm left thousands without power. Roads were flooded in parts of the San Francisco Bay Area and Sacramento County. Dozens of people trapped in vehicles were rescued by emergency services, including some by helicopter. Several victims were found clinging to trees for safety.
Levees broke along the Cosumnes River, causing flooding in Sacramento County. Evacuation orders or warnings were issued for residents in Wilton, Glanville Tract and Franklin Pond. A long stretch of State Route 99 near Elk Grove was underwater. One person died in a flooded vehicle in the area.
A second fatality was reported when the storm downed trees in Santa Cruz. Another powerful system is expected to bring further heavy rain from 04 January 2023.
Rainfall and Rivers
Record rainfall was recorded in areas of San Francisco on 31 December 2022. The National Weather Service (NWS) Bay Area reported 120.65 mm (4.47 inches) of rain fell in Oakland on 31 December 2022. This is the wettest day on record at the site, beating the previous record set in 1982. NWS also reported the San Francisco Downtown site recorded 138.68 mm (5.4 inches) which is the second wettest day in the 170-plus years of records at that site, and just short of the record (5.4 inches) set in 1994. Redwood City recorded 113.54 mm (4.47 inches) on the same day.
National Weather Service in Sacramento also reported heavy rainfall including 104.90 mm (4.13 inches) at South Lake Tahoe Airport and 155.45 mm (6.12 inches) at Blue Canyon on 31 December. The city of Sacramento recorded 62.74 mm (2.47 inches) in 24 hours to 01 January 2023.
Areas of northern California have already seen heavy rain in recent days. NWS Sacramento said December was one the wettest on record at many locations and Stockton and Modesto both had their wettest Decembers on record.
High levels of rainfall caused severe rivers to rise, in particular the Cosumnes and Mokelumne Rivers.
It’s been a busy last few days for our Air Operations Division. Many lives have been saved as a result of the proactive and hard work from our regions’ public safety agencies. pic.twitter.com/wzK8qMsMDK
— Metro Fire of Sacramento (@metrofirepio) January 2, 2023
This is Twin Cities Road (State Route 104) just east of Interstate 5 in south @SacCountyCA. It’s obviously closed due to flooding. No ETO. @CHPSouthSac @CityofElkGrove pic.twitter.com/uficQpebk8
— Caltrans District 3 (@CaltransDist3) January 2, 2023
Our San Francisco Downtown site hit 5.46” in the 24 hours of december 31st. This makes it the second wettest day in the 170+ years of records at that site, just 0.08” less than 1st place (11/5/1994) with 5.54”
This also was 46.8% of the monthly rainfall. (11.66”) pic.twitter.com/18DKkQkpG1
— NWS Bay Area 🌉 (@NWSBayArea) January 1, 2023
We have a road closure in place on US-101 for public safety reasons. When one driver chooses to drive thru the closure & others follow, you now stretch the resources even thinner. We are currenty having to rescue the submerged vehicles in addition to all other calls for service. pic.twitter.com/QMQ40J9lyU
— CHP San Francisco (@CHPSanFrancisco) January 1, 2023
OES Intel 12, Jan 1st 2023 on HWY 99 and Dillard RD, Sacramento County. pic.twitter.com/fHLhkRnK3O
— FIRIS (@FIRIS) January 2, 2023