A powerful atmospheric river storm system is expected to bring life-threatening flooding, wind, snow and waves to California this weekend.
A flood watch will be in effect for southern central California Saturday night through Tuesday. This phenomenon can lead to dangerous and life-threatening flooding, including in urban areas.
Precipitation totals of 3 to 6 inches are common, but 6 to 12 inches are possible in south- and southwest-facing hills and mountains. The heaviest rain is expected on Sunday and Monday, with up to an inch of rain possible per hour at peak times. Heavy rain is expected to last for three to six hours.
Frequent flooding of expressways is expected in densely populated areas. The lowest rainfall forecast is still enough to cause damaging flooding, according to the National Weather Service Los Angeles office.
Los Angeles Mayor Karen Bass on Sunday urged residents to stay off the streets.
“We're lucky that most of the storm hits on Sunday, when a lot of people are home anyway,” Bass said at a news conference late Saturday. “But when in doubt, stay home. Stay informed.”
City Fire Chief Christine Crowley said at a news conference that the city is fully staffed to respond to water-related emergencies and has “strengthened” its air resources in preparation for the storm.
Large rock and landslides can occur on roads in mountains and canyons, which can cause significant traffic delays and closures.
Evacuation orders were issued for parts of Santa Barbara County on Saturday, and officials said there was a high risk of flash flooding. Santa Barbara is expected to complete evacuations from house to house by Saturday evening.
“This storm is predicted to be one of the largest and most significant storms in our county's history,” Barbara County Sheriff Bill Brown warned at a press conference Saturday.
The county's state beaches will be closed until further notice, officials said. Schools will also be closed across the county on Monday.
The Ventura County Sheriff's Office also issued an evacuation order for some residents Saturday due to expected rain. The 24-hour evacuation order goes into effect at 5pm local time. Evacuation advisories were also issued for other parts of the county.
Damage from wind will also be a major problem. Wind gusts of 60 to 80 mph are expected Sunday, especially in the mountains off the coast of California.
Harmful winds blow down trees and power lines. Widespread power outages are expected. Travel will be difficult, especially if you have a large vehicle. Large-scale wind damage is expected in mountainous areas.
A high surf advisory has already been issued and will remain in place until Monday. Waves could reach heights of 20 feet and crest by Sunday.
Increased risk of drowning at sea. Rip currents can drag swimmers and surfers out to sea. Large breaking waves can cause injuries, sweep people off beaches and rocks, and capsize small boats near the shore.
The National Weather Service said no significant damage to roads or structures is expected.
A winter storm warning is also in effect for the Sierra Nevada, where very heavy snow is expected from Saturday evening into Tuesday.
Snow totals are expected to be 2 to 4 feet, with up to 5 to 6 feet on high mountain peaks.
timing the storm
Rain is expected to start falling Saturday evening and become heavier and more widespread overnight.
By Sunday morning, heavy rain is expected to fall along much of California's coast, with heavy snow in the mountains.
The heaviest rain from this storm will be concentrated in Los Angeles and surrounding areas as the Grammy Awards ceremony is being held in Los Angeles late Sunday afternoon. Flash flooding is possible, including in urban areas, and wind damage is also possible. Expect delays at Los Angeles International Airport.
Heavy rain is expected to occur in the San Diego area by Monday morning, with the possibility of flash flooding. Rain is expected to continue throughout the day and weaken further.
