An extraordinary plume of subtropical moisture moved into San Diego Monday night, in what forecasters say is the start of a meteorological chain reaction that could ultimately drop 4 to 6 inches of rain in North County and 3 to 4 inches from San Diego south to the border by Sunday.
The plume took the form of an atmospheric river that traveled from near Hawaii and was pulled into Southern California by a cold storm from the North Pacific. The river — which has already caused flooding and mudslides in Los Angeles and Orange counties — will last until early Tuesday, possibly producing the same kind of mayhem here in San Diego County.
The plume will then fade. But forecasters said that what follows will be the core of the main storm, which will lash the county well into Tuesday night. The following day, an entirely new storm will move ashore, periodically dropping moderate to heavy rain that will extend into Thursday. Scattered rain will continue into the weekend.
If San Diego receives 3 inches of rain by Sunday, that would push the city’s seasonal rainfall total to more than 8 inches. San Diego only averages 9.79 inches during the rainy season, which lasts from Oct. 1 to Sept. 30.
The plume moved into North County before dawn on Monday and dropped about 4 inches of rain at San Onofre and 3.41 inches at Camp Pendleton, along with about 2.25 inches at Oceanside and Fallbrook, through 8 p.m.
Many areas south of Carlsbad had gotten only a smattering of rain by Monday evening, leading many to wonder if the storm would simply bypass San Diego and South County, especially the areas where a Jan. 22 storm caused damaging flooding, such as Southcrest, Mountain View and National City.
But the atmospheric river soon shifted south, as forecast, and began drenching the San Diego metropolitan area. Forecasters expected the San Diego River in Fashion Valley to reach flood stage early Tuesday morning.
The initial arrival and expansion of the storm was felt throughout the county, and beyond.
More than 175 flights out of San Diego International Airport had been delayed by Monday evening, and about a third of inbound flights also had been delayed, according to FlightAware.
Monday’s rain also closed the stretch of state Route 78 between San Diego Zoo Safari Park and Bandy Canyon Road. Flooding led to road closures throughout the region, including — again — on a busy section of state Route 78 near El Camino Real in Oceanside. There was also a smattering of reports of downed trees across North County.
Conditions were even worse to the north in San Clemente, leading the city to close two new sections of beach near the spot of a landslide in late January that has halted passenger rail service between San Diego County and points north.
San Diego Mayor Todd Gloria issued evacuation warnings Sunday to several of the low-lying communities that had already suffered flood damage in earlier storms.
“This is a warning, not an order,” Gloria said. “This warning is designed to have residents in these communities make preparations now should it become necessary in the future” to evacuate. If an evacuation order is issued, first responders will go door-to-door, the mayor said.
Fire Chief Colin Stowell said the city’s Fire-Rescue Department had beefed up its staffing because of the storm, calling in extra firefighters, lifeguards and dispatchers to handle calls. He urged residents to stay home, avoid outside activities and stay off the roads if they could.
“If you do not need to go outside, if you do not need to get on the roads, don’t,” Stowell said. He reminded drivers not to go around barricades.
Nearly 160 households were temporarily placed in hotel rooms by the San Diego Housing Commission, Gloria’s office said.
The Red Cross shelter at Balboa Park hosted 91 people, nearly a third of them new to the shelter Monday. Many of the others remain displaced by Jan. 22 flooding.
The city of San Diego said it had relocated people who had been staying at the designated camping site at 20th and B Streets, offering all of the roughly 150 people at the site temporary shelter at Golden Hall.
The city also activated its inclement weather shelter program, a partnership of the San Diego Housing Commission, City of San Diego, Father Joe’s Villages, San Diego Rescue Mission and Living Water Church of the Nazarene.
There was a push to help unhoused people with pets prepare as well. Helen Woodward Animal Center’s Emergency Response Team stopped by Alpha Project and Dreams for Change, passing out dog and cat food, crates, collars, blankets and more. There was also a veterinary technician on hand to provide basic welfare checkups.
The animal center helped 85 animals and “completely ran out of supplies,” a spokesperson said.
State Attorney General Rob Bonta issued an alert Monday reminding people to beware of price-gouging. State law generally prohibits sellers from increasing prices more than 10 percent after a state of emergency has been declared — Gov. Gavin Newsom issued such a declaration over the weekend in anticipation of the deluge expected in several counties, including San Diego.
Rainfall totals through 4:18 p.m. Monday:
San Onofre: 3.56 inches
Camp Pendleton: 3.15 inches
Palomar Observatory: 2.49 inches
Oceanside: 2.02 inches
Fallbrook: 1.99 inches
Rainbow: 1.56 inches
Bonsall: 1.53 inches
Carlsbad: 1.42 inches
Vista: 1.23 inches
Encinitas: 0.96 inches
San Marcos: 0:79 inches
Valley Center: 0.79 inches
Escondido: 0.66 inches
First appeared on www.sandiegouniontribune.com