Southern California spring storm brings strong wind, heavy rain

A wet and windy storm arrived in California on Tuesday, promising to deliver more rain, snow and headaches to residents of the Golden State on the second day of spring.

The low-pressure system developed rapidly over the Pacific and made landfall along the Central Coast, where widespread rain and potentially damaging wind gusts of up to 70 mph are possible.

The greatest effects are expected in Southern California as the cold system gains some subtropical moisture — a recipe for heavy rain. Flood watches and advisories are in effect across the Southland, and roadway flooding and traffic jams were reported in Los Angeles early Tuesday.

“The heaviest rain is definitely going to be in Southern California, and L.A. and San Diego will both probably see more rain out of this storm than a lot of other storms this winter,” UCLA climate scientist Daniel Swain said during a briefing Monday.

The National Weather Service has issued high wind warnings from San Francisco to San Luis Obispo, as well as inland areas including Palmdale, Lancaster and the Antelope Valley. The winds could topple unsecured objects and take down trees, potentially resulting in blocked roads, power outages and structural damage.

The heavy rain is likely to lead to rapid runoff and areas of flooding as the storm moves south Tuesday. Heavy snow will also pose hazards in the mountains of Southern California as well as the central and southern Sierra Nevada, where up to 4 feet could accumulate at higher elevations.

“This additional snowfall will lead to difficult travel and could strain infrastructure in areas still buried under a record-breaking snowpack for the year-to-date,” the weather service said. Snowpack in the southern Sierra is at 225% of its normal for the date, according to state data.

In Southern California, the storm was expected to gain strength and deliver a cold front by Tuesday afternoon, with high temperatures likely to drop into the 50s — about 10 to 15 degrees below normal for the time of year, said David Sweet, a meteorologist with the weather service in Oxnard.

“There could be some excessive rain when the strongest part of the storm moves through, so we’ll be concerned with flooding,” Sweet said. “We’re also going to be concerned with strong winds. Winds are really picking up in the coastal waters now — they’re seeing gusts on the order of 40 and 50 mph — so it looks like the storm’s going to deliver on the winds.”

In the Los Angeles area, rainfall totals of up to 3 inches are possible along the coast and in the valleys, and up to 5 inches in foothills, Sweet said.

The storm arrives after a season of wet and destructive weather, including a series of nine back-to-back atmospheric river storms in January, which contributed to the deaths of nearly two dozen people.

In late February and early March, historic snowstorms dropped fresh powder at elevations as low as 1,000 feet — including at the Hollywood sign — and trapped residents under feet of snow in the San Bernardino Mountains, where at least 13 people died.

More storms in recent weeks saw levee breaches and devastating floods, particularly in the Monterey County town of Pajaro and in Tulare County communities near the Tule River, both of which saw evacuations and widespread property damage as floodwaters streamed from swollen rivers.

Thousands of residents in Tulare remained under evacuation orders Tuesday, including the areas of Alpaugh and Allensworth and portions of Porterville along the Tule River, where officials continued to be concerned about rising river levels as they released water from Lake Success to make room for incoming flows.

The lake was at about 96% of capacity, and officials were “continuing a high output to get it lower in anticipation of today’s rainfall and future snowmelt,” said Daniel Potter, a spokesman with the California Department of Forestry and Fire Protection, which is assisting with emergency operations and flood response in the area.

Hundreds of small levee breaks have been reported, including a breach that sent floodwaters onto properties near Allensworth. At least seven structures have been completely destroyed, more than 652 have sustained major damage and 177 took minor damage. Nearly 24,000 structures remain threatened, according to Cal Fire.

Multiple small breaks have been temporarily repaired with “super sacks,” or bags of sand and rocks, Potter said. “We’re keeping an eye on some other areas, but as of right now everything is looking good — we’re maintaining right now,” he said.

Tulare County Emergency Operations spokeswoman Carrie Monteiro said the county was vulnerable to flooding in part because of the severe drought that has gripped the region for more than a decade.

“And so our waterways had not been tested with this kind of water — the water that is going through them right now,” she said. “So we’re preparing for the next storm. We’re preparing to have tools and the resources we need on the ground. And ready to go in a significant way.”

The storm was also expected to bring up to 3 inches of rainfall in Orange County and the Inland Empire and up to 8 inches in the San Bernardino Mountains, along with higher-elevation snow.

“It’s a high amount of rain — the storm is a really strong one,” said Casey Oswant, a meteorologist with the weather service in San Diego. “In lower to mid-level elevations, we’re expecting really strong winds coming from the south, which will really intensify the orographic component of the rainfall,” meaning it will produce a lot of rain over the mountains.

Part of the challenge is the storm is falling on an already saturated state, said Swain, the UCLA scientist. Though rainfall totals are not likely to be record-breaking from this storm, the wet antecedent conditions can exacerbate flooding, erosion and other hazards.

“It’s probably not an extreme storm individually, by historical standards,” Swain said. “But once again, another significant event on top of everything that has come before is going to cause some major problems.”

Conditions are expected to clear in most of the state Thursday into Sunday, forecasters said. But yet another storm could arrive as early as next week.