Tropical Storm Hilary: Los Angeles and San Diego Evaded Major Damage, Officials Say

Rainfall records were set in Southern California, but so far there have been no reports of deaths or major storm damage in Los Angeles and San Diego, officials said. The impact in other cities is still being assessed.

Jill Cowan and Thomas Fuller

Reporting from California

As sunshine returned to Southern California on Monday, residents and officials said the region had avoided catastrophic damage from Tropical Storm Hilary, which broke records for August rainfall as it passed into California on Sunday but was much diminished from the fearsome Category 4 hurricane that had alarmed meteorologists days earlier when it was over the Pacific Ocean.

Under sheets of rain, some neighborhoods in the desert cities east of Los Angeles became a soupy mess and at one point on Monday the mayor of Palm Springs said the city was cut off by road closures. In San Bernardino and Riverside Counties, videos showed creek beds filled with sludge-colored torrents that ominously carried boulders and tree trunks.

Yet in one of the most heavily populated parts of the country — Los Angeles and San Diego Counties alone have a combined population of more than 13 million — there were no reports of deaths related to the storm as of Monday afternoon.

“I can’t remember a major storm in which we had no fatalities,” Zev Yaroslavsky, a former Los Angeles county supervisor and city councilman, said Monday. “We were prepared and, as a result, we made our own luck.”

Hilary was one of very few tropical storms to hit California over the past century. In anticipation of widespread challenges, the Los Angeles Unified School District, the nation’s second largest, had canceled classes and after-school programs on Monday. Classes were to resume Tuesday, the district said.

Crews in Los Angeles, as in other cities in Southern California and Nevada, were responding on Monday to reports of fallen trees, potholes and downed power lines, along with some road flooding. But officials generally expressed relief that things were not much worse.

“By and large, we’re feeling pretty good about it because we’re not seeing a lot of impacts to homes and residents,” said Brian Ferguson, a spokesman for the California Governor’s Office of Emergency Services. “We’re not seeing a single fatality or injury as of yet.”

Officials cautioned that some parts of the state had not yet been dug out of the mud generated by the storm. The City of Palm Desert in the Coachella Valley urged residents to use “common sense and caution” as work crews continued to respond to reports of damage. City officials said that many trees were downed and boughs broken. They advised residents to avoid parks and flooded areas.

Nearby, Michael Contreras, the chief of the Cathedral City Fire Department, said his staff rescued 46 people in 18 hours. That included 14 older residents at a board and care home who were ferried to safety with bulldozers.

In the San Bernardino Mountains, where some areas recorded more than 10 inches of rain, the storm turned roads into raging rivers filled with debris and mud. It happened so quickly on Sunday that the authorities told residents in the Forest Falls community to stay in their homes, where they were still waiting for the streets to be cleared on Monday.

State and local officials were monitoring fragile hillsides, which can still melt into a torrent of mud up to 72 hours after the clouds have cleared. “We’re not out of the woods,” Mr. Ferguson said.

In San Diego, emergency workers reported a close call: 13 homeless people were rescued from the rain-swollen San Diego River on Sunday night.

And in the mountainous Mt. Charleston area of Nevada, west of Las Vegas, residents were being advised to boil tap water before drinking it after flooding caused a severe leak in the water system.

Before reaching California, the storm dumped enormous amounts of rain on Mexico’s Baja California peninsula. Some areas recorded nearly 13 inches of rain in 24 hours, according to the country’s national coordinator of civil protection, Laura Velázquez Alzúa. The previous record was seven inches, from 1997.

Nearly 3,000 Mexican Marines were mobilized to provide aid and one person was killed by rushing floodwaters. Another was missing. But Mexico’s president, Andrés Manuel López Obrador, posted in Spanish that “fortunately, there was not much damage.”

At a time of year when Southern California is normally dangerously desiccated and very vulnerable to wildfires, some meteorologists and engineers pointed to the positive effects of the drenching rains.

Officials in Los Angeles County touted the success of projects that had sought to divert and store rainwater. As of Monday morning, Los Angeles County had captured enough storm water to supply at least 33,600 residents for a year, said Steve Frasher, a public works spokesman.

And the storm was helping to dampen fire risks in Southern California, said Daniel Swain, a wildfire expert at the University of California, Los Angeles. “There’s likely to be a prolonged reprieve in Southern California,” he said in an online briefing. “Enjoy it while you can.”

For homeowners who suffered flood damage, cleanup will be complicated by an extra challenge: In a part of the country not accustomed to tropical downpours, less than 1 percent of households have federal flood insurance. Home insurance policies typically don’t cover flooding.

But in parts of California closer to the coast, some were puzzled at why the storm had received so much attention.

As the air cleared on Tuesday, Vazken Kouftaian, 40, a resident of Santa Clarita, north of Los Angeles, took his 2-year-old son for a walk. This storm, he said, felt more like a normal rain shower. “They were expecting something very bad,” he said. “But it was nothing like that.”

Reporting was contributed by Corina Knoll from Los Angeles; Vik Jolly from San Diego; Rick Rojas from Las Vegas; Maggie Miles from Palm Springs, Calif.; Emiliano Rodríguez Mega from Mexico City; Sergio Olmos from Cathedral City, Calif.; Soumya Karlamangla from San Francisco; Shawn Hubler from Sacramento; Christopher Flavelle from Washington; and Anna Betts from New York.

Soumya Karlamangla

There have been no reports of injuries or fatalities from Hilary in California, said Brian Ferguson, a spokesman for the Governor’s Office of Emergency Services. Officials would continue to monitor soaked communities, he said, because mudslides can happen as much as 72 hours after a storm.“We’re not out of the woods,” Ferguson said.

Sergio Olmos

Some neighborhoods In Cathedral City, southeast of Palm Springs, were inundated with floodwaters overnight. Firefighters have been rescuing stranded residents, in some cases with heavy machinery.

Search for a place to see the observed precipitation.

Anna Betts

“We were very lucky,” said Molly Nichelson, a spokeswoman for Orange County, Calif. There had been no reported injuries or deaths due to the storm, she said, and only a minor road closure in Huntington Beach on Sunday. “We fared pretty well,” she said.

Due to flooding, both directions of PCH are closed between Warner & Seapoint. https://t.co/7a9tUQmbFT

Rick Rojas

Officials have blocked access to State Route 190, the highway that cuts through Death Valley National Park, which experienced heavy rainfall and flooding. One of the places where water and mud has pooled is right where the route ends, in Death Valley Junction, or Amargosa, an unincorporated area in the Mojave Desert known for its opera house.

Soumya Karlamangla

The historic rains that Tropical Storm Hilary dumped on Southern California have dampened the risk of major wildfires in the region — at least for the next several weeks.

Typically, the odds of a dangerous, fast-moving fire in California become greater each successive week in the summer and fall as brush and foliage dry out from months of scorching heat and no precipitation. But the unusual August drenching across Southern California, with some of the largest amounts recorded in the mountainous regions that are most prone to wildfires, replenished the vegetation and soil.

The heavy rains essentially limited the speed at which fires should break out, experts said.

“This has a really big fire-squashing effect,” said Park Williams, a hydroclimatologist at the University of California, Los Angeles. “I think this storm was big enough that the chances of really big fires in 2023 are substantially reduced in Southern California.”

The southeastern portion of California will benefit in particular from the rains. But there won’t be much fire protection from Hilary conferred to the Bay Area, Central Coast or northwest corner of the state, where several fires are currently burning, said Daniel Swain, a climate scientist at U.C.L.A.

The gentle rain that fell on Sunday in the Sierra Nevada “is one of the best kinds of weather you can get this time of year to attenuate fire season,” Dr. Swain said in an online briefing on Monday. “There’s likely to be a prolonged reprieve for weeks, at least, in Southern California and in places that got soaked on the eastern side of the Sierra.”

Robert Carvalho, a spokesman for the California Department of Forestry and Fire Protection, agreed that the downpours likely diminished the fire risk in some parts of the state, but he emphasized that some danger remains. Exceptionally dry places won’t suddenly become normal, healthy landscapes because of one storm, he said. And a string of hot, dry weather in the coming months could still result in major fires later this year, he said.

“If you have a tree that hasn’t had rain in a while, just because you gave it gallons and gallons of water doesn’t mean the fuel moisture will go right back up,” Carvalho said.

Already, California’s fire season has been off to a relatively calm start. Roughly 151,000 acres have burned in the state so far this year, compared with an average of 794,000 acres by this point in the previous five years, according to Cal Fire, Carvalho’s agency. Experts have credited an extraordinarily wet winter that was followed by an unusually cool spring and early summer, though the conditions appeared to be shifting in recent weeks as fires became more difficult to contain and grew larger than early-season blazes.

Anna Betts

City officials in Palm Springs are still assessing the damage caused by the storm, but as of Monday afternoon, no deaths had been reported and there had been no evacuations, said Amy Blaisdell, the city spokeswoman. There were several “minor swift water rescues,” Ms. Blaisdell said, adding that everyone had been rescued safely. The city did suffer damage to three major arteries leading to the city, but avoided injuries because the roads were closed before the storm. “We feel very fortunate,” Ms. Blaisdell said.

Corina Knoll

Dodger Stadium, many believed, was drowning in a sea of water on Sunday, doomed by its unfortunate placement in a Los Angeles ravine.

At least that’s what a murky aerial photo prompted many to speculate as it went viral, making the social media rounds during Hilary. The home of the Dodgers appeared tragically swamped and likely to be troubled for many days.

Commenters lamented that Dodger Stadium had become an island.

But on Monday the team released staggeringly different pictures of the stadium, including parking lots that looked fresh and dry. The caption: “Dodger Stadium trending? We get it. It looks beautiful this morning.”

Dodger Stadium trending? We get it. It looks beautiful this morning. pic.twitter.com/oIrZjndZoZ

According to Erik Braverman, a senior vice president of communications with the baseball team, the stadium had at one point accumulated “maybe just over an inch of water.”

“The field was completely fine,” Mr. Braverman said in an email. “The empty parking lots had water obviously, but there was no flooding or damage.”

He added, “It’s pretty wild how this became such a story. I’m sitting in my office at the stadium right now and it is a beautiful day here.”

The contrasting public perception may have had something to do with the angle and distance of the initial photo, how closely someone studied its details, and how light played off the puddles.

“You’re getting the reflection off the cloudy sky into the water, and it makes it look like, ‘Oh my gosh, it’s a massive lake.’ And that’s not the case,” said Joe Sirard, a meteorologist with the National Weather Service based in Oxnard, Calif.

“You can see the trees are high above the water. You can see there’s clues that the water is not as deep as it might appear — the parking lots are sticking way up high, and one could use deductive reasoning to realize it’s not very deep. But it looks like a big pond.”

Mr. Sirard said the total rainfall for that area since the storm began was from three to four inches.

Rick Rojas

In and around Death Valley, vast stretches of desolate, dusty highways have been interrupted in places by pools of standing water and spots made slick with mud after the storm passed through. Access to Death Valley National Park has been closed, with officials saying some roads in the park's more than 3.4 million acres of arid wilderness have been rendered impassable by standing water and debris from heavy rainfall and flash floods. It is unclear how long the park will remain closed.

Sergio Olmos

Firefighters in Cathedral City rescued the four-member crew of a Union Pacific freight train that became stranded during the storm. The crew had to stop the train because of debris flow on the tracks, and then could not get off safely on their own because of flooding around the tracks, according to Chief Michael Contreas of the Cathedral City Fire Department.

Anna Betts

The lengthy stretch of Interstate 10 that was closed in both directions near Palm Springs, causing long traffic tie-ups, has now been reopened, the City of Palm Springs announced just aftet 2 p.m.

I-10 FREEWAY HAS REOPENEDBoth directions have reopened, however eastbound traffic is being diverted off the freeway at Date Palm Drive, north to Varner, and east on Varner to renter the freeway at Monterey. pic.twitter.com/A7s5wVT1T5

Anna Betts

The City of Palm Desert, in the Coachella Valley of California, urged residents on Monday afternoon to continue to use “common sense and caution” as crews continued to respond to the damage caused by the storm. City officials said that many trees were downed and damaged and advised residents to avoid parks and flooded areas.

Anna Betts

Many trees are down in Palm Desert and some streets are flooded, according to Ryland Penta, a digital strategies coordinator for the city. But overall, he said, the city, which invested heavily in flood control measures in the 1970s and 1980s, had “fared very well” during the storm.

Vik Jolly

Swift water rescuers from San Diego fire and lifeguard crews helped bring 13 homeless people to safety on Sunday night from a pontoon on the rain-swollen San Diego River. The rescue took place at about 8:40 p.m. in the Mission Valley area under the Morena Boulevard overpass, said Chief James Gartland of the San Diego Lifeguard Division. Two people were treated at the scene and released. No other injuries were reported.

Kevin Yamamura

The Los Angeles Angels have postponed their Monday game to Wednesday evening “due to the effects from yesterday’s storm.”

Due to the effects from yesterday’s storm, tonight's game against the Reds has been rescheduled as part of a doubleheader on Wednesday, August 23rd.All tickets for Monday's rescheduled game will be honored for Game 2, with first pitch scheduled for 6:38pm. pic.twitter.com/wUvcTST3h1

Maggie Miles

Al Betancourt, 60, was definitely feeling the storm’s wrath. He was waiting for a tow truck by the side of his vehicle, its hood open, after running into muddy waters in Thousand Palms, Calif., on Monday. He had gotten stuck on the way to help his son, who was also stranded because of Hilary’s rain. Mr. Betancourt said about 6 inches of floodwater had entered his home in that same community. One of his neighbors had about 10 inches of flooding. “But we all helped each other out, helped each other move our furniture,” he said. Mr. Betancourt said he was relieved to find that his son was OK. “I don’t care about the car. It’s crazy. I’ve been living here since 1976 and I’ve never seen it like this. This is bad.”

Vik Jolly

County and city officials in San Diego, Calif., credited their preparations, the public’s response to social media messages asking people to stay home as well as news reports and a milder-than-expected tropical storm in reducing the weather system’s impact. They reported no loss of life and no major structural damage at a midday news conference on Monday.

Jill Cowan

Along the Los Angeles River in Frogtown, a rapidly gentrifying neighborhood where formerly industrial buildings have been transformed into cafes and new bungalows and apartments have replaced blocks of small houses, walkers and bikers paused to take in views of the rushing — but not particularly high — water. The streets were clear and the homes appeared undamaged.

Soumya Karlamangla

The storm caused local flooding across San Bernardino County, and mudslides in rural communities like Forest Falls and Oak Glen, said David Wert, a spokesman for the county. “Crews are out in force surveying the situation, helping residents, and using heavy equipment to clear roads,” he said in an email, adding that the county had no confirmed reports of serious injuries or missing people.

Maggie Miles

Victor Ruiz, a resident of Thousand Palms in Riverside County, Calif., was towed by a fellow driver out of thick, muddy floodwater at the intersection of Varner Road and Monterey Avenue in Thousand Palms on Monday morning. Waters were rising on the roads as they continued to flow from the San Jacinto Mountains after the rain. Mr. Ruiz said he was caught on the way to Cathedral City, "to check on my other place there."

Christopher Flavelle

Southern California’s recovery from Hilary will be impeded by an extra challenge: Almost nobody in the region has federal flood insurance.

Home insurance policies typically don’t cover flooding, which is most commonly covered separately through the federal government’s National Flood Insurance Program. But in the areas of California that were hardest hit by the remnants of the hurricane, less than 1 percent of households carry that coverage.

In Palm Springs, no more than 167, or 0.7 percent, of the city’s roughly 24,000 households have flood insurance policies, according to data from the Federal Emergency Management Agency, which runs the federal program. (The actual share of households with coverage is probably even smaller, as FEMA’s data covers both homes and businesses.)

In Riverside County, which includes Palm Springs, that figure is 0.6 percent. In Inyo County, which was also affected by flooding, the figure is 0.9 percent.

(Those figures don’t include people with private flood insurance, a niche product that covers far fewer households nationwide than the federal program.)

The lack of coverage probably reflects two things. One is the way flood insurance works: It’s mandatory for homes inside federally designated flood zones, if those homes carry a mortgage. But outside flood zones, homeowners can decide whether to buy coverage. That coverage is expensive — annual costs average $1,689 for somebody buying flood insurance in California for the first time, FEMA data shows.

So people outside flood zones are left to decide whether flood insurance is worth it. Many people will make that decision based on personal experience: Does their area tend to flood? The answer is Southern California is typically no: Hilary was the first tropical storm to hit the state in 26 years.

The fact that a vast majority of Southern California households lack flood insurance will slow the recovery process. Federal disaster aid isn’t designed to replace insurance, and disaster survivors are often surprised to learn that they can’t get enough federal aid to cover the cost of repairing their home. Many are left to rely on their savings or charity.

Shawn Hubler

Los Angeles’s experience with natural disasters has made its emergency preparedness system one of the most sophisticated in the nation, one former local official said. The public largely stayed off the road as instructed. And not only did alerts work, but some residents complained that they were over-alerted. “I can’t remember a major storm in which we had no fatalities,” Zev Yaroslavsky, a former county supervisor and city councilman, said Monday. “We were prepared and, as a result, we made our own luck.”

Jill Cowan

Vazken Kouftaian, 40, a resident of the Santa Clarita neighborhood called Canyon Country, took his 2-year-old son for a walk in the clear air. He said that the area around Placerita Canyon had been “full of water” for months since winter storms wreaked havoc on California, so it had been nice to be able to visit this summer. This storm, he said, felt more like a normal rain shower. Based on what he was hearing on television and seeing on social media, “They were expecting something very bad,” he said. “But it was nothing like that.”

Becca Carballo

Nevadans in the Mt. Charleston area are under a boil water advisory, the Kyle Canyon Water District announced on Monday. On Sunday night, flooding caused a severe leak in the water system, resulting in the major reservoir tanks losing pressure. Officials were advising all Kyle Canyon customers to boil tap water before drinking it, preparing food, brushing teeth, washing dishes and making ice, until further notice.

Jill Cowan

The winding Placerita Canyon Road in Santa Clarita, about 30 miles north of downtown Los Angeles, was lined with mud and rocks that were washed down by the storm, but it was easily passable on Monday. The golden, red and green hillsides in the canyon were lush and damp after the rain, and the air smelled earthy and herbal. But visitors arriving at the Placerita Canyon Natural Area found the park closed.

Jill Cowan

Sam Fick and Kimmi Koch, both 35, brought a group of several young kids, whose school was canceled, in galoshes and shorts to the park. Both mothers said they visit the park often with their families, and they were surprised to find it closed on Monday. They decided to venture in anyway. “Look! There’s your first puddle!” Ms. Koch called out as the kids splashed. Ms. Fick pointed out a creek rushing under a bridge, where she said there had been no water just a couple days ago.

Emiliano Rodríguez Mega

The Mexican state of Baja California Sur registered record levels of rainfall throughout the weekend after Hilary dumped 13 inches of rain in 24 hours, the country’s national coordinator of civil protection, Laura Velázquez Alzúa, told reporters on Monday. The previous record of 7 inches was from 1997.

Emiliano Rodríguez Mega

Ms. Velázquez Alzúa said that a new tropical cyclone has formed in the Gulf of Mexico and is expected to reach Texas on Tuesday afternoon, adding that rains would also shower the northern Mexican states of Nuevo León and Tamaulipas, “which we very much need.” Both states have experienced drought throughout the year.

Soumya Karlamangla

A voluntary evacuation period has now ended in a number of small desert communities in Imperial County, Calif. Officials told residents of Ocotillo, Salton City, Salton Sea Beach, Bombay Beach and Desert Shores that it was safe to return to their homes, though warned them to watch out for debris, standing water and road damage.

Shawn Hubler

In drought-prone Los Angeles County, where officials have invested heavily to prevent rain from running off into the Pacific Ocean, Hilary was a windfall. As of 8 a.m. Monday, the county had captured enough stormwater to supply at least 33,600 residents for a year, said Steve Frasher, a public works spokesman.

Maggie Miles

A truck cleared flooding on the eastbound lane of Interstate 10 at Monterey Avenue, in Thousand Palms, Calif., on Monday morning, while truck traffic had slowed to a halt on the westbound side as a result of flooding from the rain brought by Hilary. The highway is a major route for freight from ports in Los Angeles to make its way across California and to other states.

Corina Knoll

Officials in Los Angeles County urge beachgoers to stay out of the water until Thursday evening, at least. After a storm, ocean water near shore can be contaminated with bacteria, chemicals, debris and trash.

Maggie Miles

A seemingly endless line of semi trucks were at a standstill, stuck in traffic near road closures at Interstate 10 and Monterrey Avenue in Thousand Palms, Calif.

Jill Cowan

At the Sepulveda Basin Recreation Area, a complex of sports fields and walking trails in the San Fernando Valley that also serves as flood control, a few puddles and downed tree branches were the most visible effects of the storm. Drivers were moving smoothly on Balboa Boulevard, and joggers passed in windbreakers.

Becca Carballo

Palm Springs residents can go back to calling 911 for emergencies. The 911 system in the city went down at roughly 10 p.m. Sunday, and officials asked residents to call a non-emergency number for the Palm Springs Police Department instead. The 911 system is still down, but Frontier Communications is now automatically rerouting 911 calls to a working line, said Lt. Gus Araiza, a police spokesperson.

Emiliano Rodríguez Mega

Mexican authorities continue to assess the damage the storm caused there before crossing into California. Nearly 3,000 Mexican Marines were mobilized to provide aid in parts of the Baja California peninsula, the military said Sunday night, and the navy rescued the municipal president of Mulegé, the coordinator of civil protection for the state of Baja California Sur, four military officials and 13 citizens from floods.

Shawn Hubler

About 18,000 customers remain without power in Los Angeles, city authorities report. It’s worth noting that the city of Los Angeles is just one of 88 cities in the county, albeit the largest.

Maggie Miles

The ambulance bay at Eisenhower Medical Center in Rancho Mirage, Calif., is flooded and unusable, but aside from that, the hospital is fully functional, according to a spokesperson, Lee Rice. A staff member posted video of a surgeon, Dr. Michael Hetzel, navigating the flood outside the hospital standing on a paddleboard.

Maggie Miles

“There is no way in or out of Palm Springs,” Mayor Grace Garner said in an interview on CNN Monday morning.

Maggie Miles

Cleanup is underway in the Coachella Valley, with schools and businesses closed and about 30 road closures in effect across Riverside County. The San Jacinto Mountains, whose eastern slopes drain into the valley, received over 10 inches of rain on Sunday night.

Shawn Hubler

“It was only a few days ago that we all walked into one of the most significant weather events of our lives,” said Ariel Cohen, meteorologist at the National Weather Service in Oxnard, Calif., noting that Hilary was the first tropical cyclone to affect Southern California in decades. “And yet not one single serious injury or fatality in Los Angeles County and Ventura County.” Mr. Cohen said the worst of the storm is probably over.

Judson Jones

San Diego, Palm Springs and a number of other California cities have broken single-day rainfall records for August, according to the National Weather Service in San Diego. In most of those places, the previous records dated from when the remains of Hurricane Doreen drenched the region in 1977.

Are you wondering how Sunday stacked up to the wettest day on record in August? pic.twitter.com/5GzKcrh4DE

Judson Jones

Sunday was also the wettest August day in Los Angeles, according to forecasters with the Weather Office.

Shawn Hubler

Alberto M. Carvalho, the superintendent of the Los Angeles Unified School District, the nation’s second largest, says the district's schools, which are closed today, are expected to reopen Tuesday.

Vik Jolly

San Diegans awakened to gray skies and some light drizzle Monday. Some low-lying streets were closed to through traffic, and local flooding and debris blocked some roads. But aside from that, San Diego appeared to have been spared the worst of the storm.

Shawn Hubler

“For most cities, Los Angeles was tested but we came through it, and we came through it with minimal impacts,” said the president of the Los Angeles City Council, Paul Krekorian. “For most cities, a tropical storm combined with a hurricane would be a catastrophic event. For Los Angeles and for our first responders, it’s just another day at the office.”

Raymond Zhong

With California’s alternating — and intensifying — cycles of drought and heavy rain, the state’s future depends on its ability to hold onto every drop of water it can. Parts of California are prepared to capture and store some of the rain from Tropical Storm Hilary, but in other areas, much of the watery bounty is likely to rush unchecked out to sea.

Los Angeles County has a number of infrastructure projects aimed at grabbing and cleaning storm flows, including basins near rivers where water can pool and percolate into underground aquifers. Since October, the county has captured over 330,000 acre-feet of water from 26.1 inches of rainfall, according to government data. (An acre-foot is the amount used by two to three households a year.)

Orange County diverts storm flows from its stretch of the Santa Ana River into more than two dozen groundwater-recharging basins. San Diego has pilot projects to capture runoff from roads, parking lots and the top of a parking plaza at its airport.

In Southern California’s parched desert interior, however, the climate and the landscape aren’t conducive to large projects for capturing water from the sky and holding it underground, said Michael Anderson, California’s state climatologist.

“The good news is that, because of the largely sandy soils, a lot of the water does soak in,” Dr. Anderson said. “The bad news is, with the steep terrain, it’s a whole lot of water rushing really fast, and so you do get that flash flooding.”

Storms like Hilary are so rare for that part of California, and last only a few days when they do sweep through, that it is not economical to build the infrastructure that would be needed to corral the floods, Dr. Anderson said.

Nikita Richardson

In recent years, the prospect of heavy rains might have sounded good to many people living in California, where drought and wildfires have been the main worries.

That was not the case on this weekend, as Hurricane Hilary moved north from the coast of Baja California in Mexico and threatened to dump six to 10 inches of rain on the region.

After three of the driest years in California history, much of the state is currently free of drought conditions, according to the U.S. Drought Monitor. Storms fueled by “atmospheric rivers” this winter led to flooding and destruction across the state, but they also relieved severe drought conditions across wide swaths of the state, including Los Angeles and San Diego Counties, both of which were in Hilary’s path.

Heavy winter rain, as well as record amounts of snow in the Sierra Nevada mountains, also has filled many of the state’s reservoirs well above historical averages, according to California Water Watch, a daily tracker maintained by the California Department of Water Resources.

And while wildfires remain a threat across the state, this year’s fire season has been significantly less destructive when compared with a five-year average of fire incidents and acres burned.

“We are quieter this season because of the large amount of rain and snow that we received over the winter — historic amounts in some cases,” said Capt. Robert Foxworthy, the information officer for the California Department of Forestry and Fire Protection.

Alex Hall, a professor of atmospheric and oceanic science at the University of California, Los Angeles, said that dry and wet weather events have been made worse, or “juiced,” by climate change.

“The net effect is we do have much deeper extremes,” Dr. Hall said. “It’s boomier and bustier. People have used the word ‘whiplash’ before.”

Aline Corpus

Reporting from Tijuana, Mexico

Two months ago, José de Jesús Torres, 52, fled his home state of Michoacán, traveling to the Mexico-U.S. border in hopes of receiving asylum in the United States.

Like many other Mexicans at the border, his family had been displaced by violence gripping states like his own and Guerrero, where drug cartels have taken control of villages and towns. The storm has put the migrant population in Tijuana in an even more vulnerable position, since most of the camps and shelters lack the basic conditions to withstand even light rain.

While waiting for an asylum appointment in the border city of Tijuana, Mr. Torres found himself not only escaping violence but also a life-threatening tropical storm on Friday.

That night, he and his teenage daughter, Areli, were staying in an overcrowded displacement camp south of the city, sleeping out in the open when the strong winds threatened to rip off the tarp tent covering them. “It was almost blown away and the hurricane had not yet arrived,” he said.

They didn’t take any risks. Mr. Torres and Areli were the first ones to arrive on Saturday morning at a temporary shelter in a sports complex full of cots — one of the six set up by the Tijuana city government in response to Hilary.

On Sunday morning, a group of 10 Colombian asylum seekers, including four women and a girl, tried to turn themselves in to U.S. Border Patrol officials as Hilary made its way into California. The migrants crossed the heavily polluted Tijuana River into U.S. territory, and waited to be processed in the rain. As of Sunday evening, it wasn’t clear if they had been admitted by immigration authorities.

Later in the afternoon, flooding and heavy rains started affecting the southwest of the city. At the Ambassadors of Jesus Church, a migrant shelter housing some 1,600 people, water had completely surrounded the building, said Father Gustavo Banda, who operates the shelter.

Enrique Lucero, Tijuana’s director of migrant affairs, said Mr. Banda’s shelter was on high alert because of the amount of mud that had accumulated around it as a result of the storm.

“With these phenomena, migrants and citizens are always at risk,” he said.

Somini Sengupta

Tropical Storm Hilary is an extraordinarily rare event for California. It will take scientists a while to figure out whether and to what extent it is influenced by human-made climate change.

But there is little question that climate change, driven by the burning of fossil fuels, is supercharging storms like this one.

A warmer atmosphere can hold more moisture. That means short, heavy bursts of rain. Expect more in the coming decades as the world continues to warm, even in the arid southwestern United States.

“Though someone can’t say right now how much more severe Hilary is because of climate change (this will require a careful statistical analysis) we are confident that climate change will generally make hurricanes rainier,” Morgan E. O’Neill, assistant professor of atmospheric science at Stanford University, said by email. “This is a robust conclusion from simple thermodynamics: Warmer atmospheres contain exponentially more water vapor, so there is more water for a storm to wring out as rain.”

When it comes to tropical storms like Hilary, there is widespread agreement among scientists that climate change has made them stronger and more destructive.

Climate models had long predicted that warmer ocean water would give storms more energy. Then, a landmark 2020 study, using satellite images, confirmed that indeed, stronger hurricanes — Category 3 or higher, with wind speeds greater than 110 miles per hour — had become more likely over the last 40 years. In other words, recent observational data were consistent with theoretical models.

What does that mean for California residents? While they may not have to worry about more frequent hurricanes, they do have to worry about more extreme rainfall — and more flooding — from what are known as atmospheric river events, which Southern California got a taste of earlier this year.

“Regardless of the source of the rain, we need to prepare for a lot more of it, even in our drought-prone state,” Dr. O’Neill said.

Thomas Fuller and Soumya Karlamangla

Reporting from California

All of California’s vulnerabilities seemed to be on display on Sunday afternoon. In addition to the lashing rains of a very rare tropical storm, firefighters near the Oregon border were battling a wildfire that grew by 2,000 acres overnight.

And then the ground shook.

The 5.1-magnitude earthquake centered near Ojai, Calif., was unlikely to have caused serious damage. But residents in Los Angeles, 60 miles southeast of the epicenter, felt swaying that lasted long enough to take notice.

A 3.5-magnitude earthquake often feels like a quick jolt, as if someone just bumped into your desk. The Ojai earthquake was slightly more significant than that and may have caused some minor cracking in walls, according to Jana Pursley, a geophysicist with the U.S. Geological Survey.

Though the earthquake was felt in much of Santa Barbara County, just 15 miles from Ojai, there haven’t been reports of damage so far, said Jackie Ruiz, public information officer for the Santa Barbara County Office of Emergency Management.

“Generally it’s sounding as if people felt the shake, and they got the alerts, and no impacts,” Ms. Ruiz said.

She said that local officials on Sunday were juggling multiple emergencies, with rainfall from the tropical storm expected to peak between 4 p.m. and 10 p.m., and a fire that began on Saturday in the northern part of the county continuing to burn.

“Absolutely a busy day,” Ms. Ruiz said.

But Sunday’s earthquake was moderate compared to some of the larger ones that have caused extensive destruction in California. The 6.7-magnitude earthquake that struck the Northridge neighborhood of Los Angeles in 1994 released 125 times more energy than today’s Ojai earthquake.

The Loma Prieta earthquake, which left more than 60 people dead in the San Francisco Bay Area in 1989, was 253 times more powerful than the Ojai quake.