Follow our live updates on Hurricane Hilary.
Tropical storm Hilary made landfall on the Baja California peninsula in Mexico on Sunday as it headed toward the United States, where it could cause heavy rain and dangerous flooding even after weakening.
The storm, which weakened on Sunday morning to a tropical storm from a Category 1 hurricane, was about 115 miles south-southeast of San Diego as of 4 p.m. on Sunday, the National Weather Service’s National Hurricane Center said in an advisory.
Meteorologists have said that the storm will bring a “potentially historic” amount of rain that may cause “life-threatening” and “catastrophic” flooding in Baja and the Southwestern United States through Monday.
Tornadoes are possible tonight in southeast California, western Arizona, southern Nevada and far southwest Utah, forecasters said.
One person died in Mexico on Saturday night after a family’s vehicle was swept away by the current of a stream in Mulegé, Baja California Sur, the Mexican authorities said.
A tropical storm warning in effect early Sunday indicated that tropical storm conditions were possible within the coverage area over the next 36 hours. The area stretched from the California-Mexico border to Point Mugu, around 40 miles west of Santa Monica by road, and includes Catalina Island.
The warning was the first ever issued for Southern California, according to the Hurricane Center.
Hilary had sustained winds near 65 miles per hour, the Hurricane Center said.
A number of events in the Los Angeles area this weekend, including a Major League Soccer match and several Major League Baseball games, have been rescheduled because of the storm.
Hilary formed as a tropical storm off the coast of Manzanillo, Mexico, on Wednesday and began moving west-northwest toward Baja California as it strengthened.
Hilary is expected to continue to weaken as it moves along the west coast of the Baja California peninsula on Sunday. It will likely dissipate over the western United States on Monday.
The storm is expected to bring up to six inches of rain across portions of the Baja California Peninsula through Sunday night, with isolated amounts up to 10 inches and the possibility of flash flooding.
Portions of Southern California and Southern Nevada will record similar rainfall totals through Tuesday morning, which could lead to “dangerous and locally catastrophic flooding,” forecasters said.
Some arid regions of Nevada could record one to two years’ worth of rain in a single day, the Weather Prediction Center said.
Residents in Southern California raced to prepare sandbags and fill generators ahead of Hilary’s arrival as emergency officials prepared evacuation centers.
The San Bernardino Sheriff’s Office on Saturday night ordered residents of several communities to evacuate. Officials in Orange County urged people in Silverado Canyon and Williams Canyon to evacuate, and said the warning could become mandatory quickly if conditions changed.
Forecasters said that strong winds could occur ahead of the storm’s center. Those winds, combined with heavy rain, could lead to mudslides, landslides and debris flows later on Sunday through early Monday morning, the National Hurricane Center said.
In Mexico, flooding and mudslides have closed a section of the highway in the state of Baja California Sur, according to Mexico’s defense ministry.
Mexico’s government issued a tropical storm warning for the west side of the Baja California peninsula from Puerto San Andresito, north, and on the east side of the peninsula from Loreto, north. A tropical storm warning was also in effect for the mainland north of Guaymas.
The Mexican army mobilized troops in anticipation of severe damage to infrastructure. Nearly 1,500 people were in shelters, officials said.
Very strong gusts of wind and high waves were recorded on Sunday morning, with waves reaching heights over 40 feet off the coast of Baja California and in the Gulf of California, according to the center.
The Eastern Pacific hurricane season has been active this summer, but most storms have tracked west toward Hawaii, including Hurricane Dora, which helped enhance extreme winds that led to the devastating wildfires on Maui.
It is “exceedingly rare” for a tropical storm to come off the ocean and make landfall in California, said Stefanie Sullivan, a forecaster with the National Weather Service in San Diego. The only tropical cyclone truly to make landfall in Southern California was an unnamed storm in 1939 that reached Long Beach, she said.
However, storms have come close or weakened before coming ashore, still causing flooding and dangerous winds, like Kay, a post-tropical cyclone, last year.
There is a consensus among scientists that hurricanes are becoming more powerful because of climate change. Although there might not be more named storms overall, the likelihood of major hurricanes is increasing.
Climate change is also affecting the amount of rain that storms can produce. In a warming world, the air can hold more moisture, which means a named storm can hold and produce more rainfall, as Hurricane Harvey did in Texas in 2017, when some areas received more than 40 inches of rain in less than 48 hours.
Researchers have also found that storms have slowed down over the past few decades.
When a storm slows down over water, it increases the amount of moisture it can absorb. When the storm slows over land, it increases the amount of rain that falls over a single location, as with Hurricane Dorian in 2019, which slowed to a crawl over the northwestern Bahamas, resulting in 22.84 inches of rain at Hope Town over the storm’s duration.
Research shows climate change might have other effects as well, including storm surge, rapid intensification and a broader reach of tropical systems.
Derrick Bryson Taylor, Jesus Jiménez, Orlando Mayorquin, Amanda Holpuch, Mike Ives, Eduardo Medina and Emiliano Rodríguez Mega contributed reporting.