(Los Angeles) The ninth atmospheric river in a series of major winter storms that lasted three weeks crossed California on Monday, making mountain driving dangerous and the risk of flooding high near flooded rivers, even if the sun appeared in some areas.
Heavy snowfall fell in the Sierra Nevada, and the National Weather Service advised against travel. Interstate 80, a key highway connecting the San Francisco Bay Area to Lake Tahoe ski resorts, has reopened to vehicles with chain tires after periodic weekend closures due to weather conditions.
“If you must travel, be prepared for dangerous travel conditions, significant delays and road closures,” the Sacramento Weather Service office said on Twitter.
The University of California, Berkeley’s Central Sierra Snow Lab tweeted Monday morning that it had recorded 126cm of fresh snowfall since Friday.
A backcountry avalanche warning has been issued for the Central Sierra, including the Tahoe area.
A saturated environment
A barrage of atmospheric rivers has dumped rain and snow on California since late December, knocking out power to thousands and flooding roads, releasing debris flows and triggering landslides. Monday’s system was relatively weak compared to previous storms, but the risk of flooding and mudslides remained due to saturation, forecasters said.
Mostly dry days were forecast for the week, although parts of Northern California may see more rain midweek.
The sun emerged Monday in San Francisco, where 51.5 cm of rain fell at the city’s airport since 1er October, when California typically begins recording rainfall for the year. The average for the “water year” is 19.6 in (49.8 cm). “So we have exceeded the annual total with eight months to go,” the San Francisco Weather Service office tweeted.
Across the bay in Berkeley, 10 homes were evacuated on Monday when a hill collapsed throwing mud onto properties. No injuries were reported.
Floods and flooding rivers
Up to 2 inches of additional rain fell in the Sacramento Valley on Sunday, where residents of Wilton and surrounding communities were warned to prepare to leave if the Cosumnes River continues to rise.
In Monterey County, the swollen Salinas River submerged farmland over the weekend and authorities said Monday it was continuing to rise. To the east, flood warnings were still in effect for Merced County in the agricultural Central Valley, where Gov. Gavin Newsom visited on Saturday.
On Monday, Newsom signed an executive order aimed at bolstering the state’s emergency response to storms and helping communities that have suffered damage.
President Joe Biden has declared a major disaster in the state and ordered federal aid to supplement local recovery efforts.
In Southern California, the sun shone in Los Angeles, but winter storm warnings and advisories were still in place for mountainous areas, where many roads remained impassable due to mud and landslides. Two lanes of northbound Interstate 5 near Castaic in northern Los Angeles County were closed indefinitely after a hill collapsed.
Downtown Los Angeles set a rainfall record on Saturday with 1.8 inches of rain, according to the weather service.
At least 20 storm-related deaths have been recorded, and a 5-year-old boy remains missing after floodwaters swept away in his mother’s car in San Luis Obispo County.
Forecasters had their eyes on a storm forming in the Pacific to see if it gains enough strength to become the tenth atmospheric river of the season in the state. Either way, it’s likely to bring only light rain and be mostly confined to northern California when it makes landfall on Wednesday, climatologist Mike Anderson said Monday during a weather briefing from the state.