Rain

October Storm: How Much Rain Fell in Southern California?

A storm fueled by an atmospheric river over the Pacific Ocean drenched Northern California and weakened as it moved south toward Los Angeles. Still, SoCal received an impressive soaking.

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From sites of debris flow to flooded intersections, NBC4’s team coverage covers the SoCal region, showing you how this rain is benefiting our drought-vulnerable landscape Oct. 25, 2021.

A powerful storm that swept through California set rainfall records in the north, but weakened as it moved south into the Los Angeles area. 

The system, powered by an atmospheric river, still produced a few daily records in SoCal and the most significant rainfall in months, enough to cause mudslides that closed roads in the San Bernardino Mountains. Most areas in Southern California received less than an inch of rain by late afternoon, although Pasadena recorded 1.11 inches.

Here are more rainfall totals for SoCal. Click here for a full list from the National Weather Service.

  • Long Beach Airport: 0.13 inches, breaking the old record of 0.08 inches set in 2010.
  • Camarillo Airport: 0.7 inches, breaking old record of 0.39 inches set in 1940
  • Los Angeles International Airport: 0.39 inches, breaking old record of 0.19 inches set in 1951.
  • Santa Barbara Airport: 0.96 inches, breaking the old record of 0.02 inches set in 2000.
  • La Cañada Flintridge: 1.31 inches
  • Coto De Caza: 0.71 inches
  • Whittier: 0.55 inches
  • Northridge: 0.53 inches
  • Downtown Los Angeles: 0.49 inches
  • Avalon Harbor: 0.15 inches
  • Santa Monica Airport: 0.47 inches
  • UCLA: 0.51 inches
  • Chatsworth: 0.46 inches
  • Saugus: 0.34 inches
  • Van Nuys: 0.47 inches
  • Lancaster: 0.28 inches

Records also were set at Paso Robles Airport (1.54 inches, breaking old record of 0.18 inches set in 1950) and Santa Maria Airport (1.28 inches, breaking old record of 0.3 inches set in 1951).

Caltrans
A rock slide covers part of Highway 70 in Butte County Monday Oct. 25, 2021.
Caltrans
A rock slide covers part of Highway 70 in Butte County Monday Oct. 25, 2021.
AP Photo/Noah Berger
Rocks and vegetation cover Highway 70 following a landslide in the Dixie Fire zone on Sunday, Oct. 24, 2021, in Plumas County, Calif. Heavy rains blanketing Northern California created slide and flood hazards in land scorched during last summer’s wildfires.
AP Photo/Ethan Swope
A car drives on Highway 101, which is partially flooded in Corte Madera, Calif., Sunday, Oct. 24, 2021.
Jonathan Lloyd/NBCLA
A view of clouds over downtown Los Angeles as seen from Mount Lee on Sunday Oct. 24, 2021.
Getty
Adrian Montellano places sand bags near a gate at Brookside Golf Club is preparation for rain on Monday, Oct. 25, 2021 in Pasadena, CA. A rainstorm is making its way down the coast and has hit Santa Barbara. Up to 1-and-a-half inches of rain is expected to fall in Los Angeles County today. (Francine Orr / Los Angeles Timesp)
Caltrans
A Caltrans traffic camera shows snow-covered roads in the Truckee area.
Caltrans
Boulders on the roadway on Highway 50 over Echo Summit.
Santa Barbara County Fire Department
A view of the Alisal Fire burn area in Santa Barbara County, where evacuations were ordered for resident in the area due to the threat of slides.
Santa Barbara County Fire Department
A view of the Alisal Fire burn area in Santa Barbara County, where evacuations were ordered for resident in the area due to the threat of slides.
NPS
Snowfall in Sequoia and Kings Canyon National Park
San Francisco Fire Department
The San Francisco Fire Department posted video on their social media pages of people doing what they can to push water into storm drains during Sunday’s rain. (October 24, 2021)
Justin Sullivan/Getty Images
Cars try to navigate a flooded street on October 24, 2021 in San Rafael, California.
Christie Smith
A scaffolding collapsed in San Francisco due to strong winds and heavy rain. (Oct. 24, 2021)
A view of the Los Angeles River channel in Universal city Monday Oct. 25, 2021.
Noah Berger/AP Photo
A pickup truck crosses a flooded parking lot in Oroville, Calif., on Monday, Oct. 25, 2021. A massive storm barreled toward Southern California on Monday after causing flooding across the northern half of the state.
NPS
At Yosemite National Park, six inches of rain fell in Yosemite Valley over a 36-hour period. Sensors suggested a few feet of snow at the higher elevations.
NPS
At Yosemite National Park, six inches of rain fell in Yosemite Valley over a 36-hour period. Sensors suggested a few feet of snow at the higher elevations.

To the north, the National Weather Service called preliminary rainfall totals “staggering,” including 11 inches at the base of Marin County’s Mount Tamalpais and 4 inches in downtown San Francisco, the fourth-wettest day ever for the city.

“It’s been a memorable past 24 hours for the Bay Area as the long talked-about atmospheric river rolled through the region,” the local weather office said Monday. “We literally have gone from fire/drought conditions to flooding in one storm cycle.”

Northeast of San Francisco, 5.44 inches fell on downtown Sacramento, shattering the one-day record for rainfall that had stood since 1880.

Along the central coast, nearly 5.4 inches  of rain was recorded at California Polytechnic State University in San Luis Obispo County. 

Interstate 80, the major highway through the Sierra Nevada Mountains to Reno, Nevada, was shut down by heavy snow early Monday. In California’s Colusa and Yolo counties, state highways 16 and 20 were shut for several miles because of mudslides, the state Department of Transportation said.

In the Yosemite Valley, the dormant Yosemite Falls roared back to life. More than six inches of rain fell across the valley during a 36-hour period.

Lake Oroville, a major Northern California reservoir, saw its water levels rise 20 feet over the past week, according to the state’s Department of Water Resource. Most of the increase came between Saturday and Monday, during the height of the storm.

Justin Mankin, a geography professor at Dartmouth College and co-lead of the Drought Task Force at the National Oceanic and Atmospheric Administration, said the cycle of going from years-long drought to record-breaking downpours is something expected to continue because of climate change.

Daylight is getting shorter as we head towards the date we "fall back" after Daylight Saving Time, but the air is cool and clear after Monday's rainstorm. There's great air quality all across the region, and refreshing fall temperatures. High surf advisories are still in effect until Wednesday. Belen De Leon has the forecast for Tuesday, Oct. 26, 2021.

“While this rain is welcome, it comes with these hazards, and it won’t necessarily end the drought,” Mankin said. “California still needs more precipitation, and it really needs it in high elevations and spread out over a longer time so it’s not hazardous.”

The long-term forecast for California shows drier-than-normal conditions, Mankin said.

“To end different aspects of the drought, you are going to need a situation where parts of California get precipitation over the next three months that’s about 200% of normal,” he said, adding that “despite this really, really insane rainfall, the winter is probably going to be drier than average.”

Copyright AP - Associated Press
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