CABO SAN LUCAS, Mexico >> Hurricane Hilary roared toward Mexico’s Baja California peninsula late Saturday as a downgraded but still dangerous Category 2 hurricane that’s likely to bring “catastrophic” flooding to the region and cross into the southwest U.S. as a tropical storm.

Meteorologists warned that despite the hurricane’s weakening, the storm’s speed had accelerated Saturday and remained treacherous. One person drowned Saturday in Mexico’s town of Santa Rosalia, along the peninsula’s eastern coast, when their vehicle was swept away in an overflowing stream. Rescue workers managed to rescue four other people, according to Edith Aguilar Villavicencio, the mayor of Mulege township.

While it was not immediately clear whether officials consider the fatality to be related to the hurricane, footage posted by local officials showed torrents of water coursing through the town’s streets.

Forecasters said the storm is still expected to enter the history books as the first tropical storm to hit Southern California in 84 years, and bring along flash floods, mudslides, isolated tornadoes, high winds and widespread power outages.

California Gov. Gavin Newsom proclaimed a state of emergency on Saturday, and officials urged people to finish their preparations by sundown. By Sunday, one expert said, it would be too late.

The hurricane is the latest major climate disaster to wreak havoc across the U.S., Canada and Mexico. Hawaii’s island of Maui is still reeling from last week’s blaze that killed over 100 people and scorched the historic town of Lahaina, making it the deadliest U.S. wildfire in more than a century. In Canada, firefighters on Saturday continued to battle blazes during the nation’s worst fire season on record.

Meanwhile, Hilary brought heavy rainfall and flooding to Mexico and the southwestern U.S. on Saturday, ahead of the storm’s expected Sunday border crossing. It’s expected to dump up to 10 inches (25 centimeters) — a year’s worth of rain for some areas — in southern California and southern Nevada.

“This does not lessen the threat, especially the flood threat,” said Jamie Rhome, the U.S. National Hurricane Center’s deputy director, during a Saturday briefing to announce the storm’s downgraded status. “Don’t let the weakening trend and the intensity lower your guard.”

Meteorologists also expect the storm to churn up “life-threatening” surf conditions and rip currents — including towering waves up to 40 feet (12 meters) high — along Mexico’s Pacific coast. Dozens sought refuge at storm shelters in the twin resorts of Los Cabos, at the southern tip of the Baja peninsula, and firefighters used an inflatable boat to rescue a family in San Jose del Cabo after the resort was hit by driving rain and wind.

In Tijuana, Rafael Carrillo voiced the fear that was at the back of everyone’s mind in the border city of 1.9 million, particularly residents who live in homes that cling precariously to steep hillsides.

“If you hear noises, or the ground cracking, it is important for you to check it and get out as fast as possible, because the ground can weaken and your home could collapse,” said Carrillo, head of the Tijuana fire department.

That city ordered all beaches closed Saturday, and set up a half-dozen storm shelters at sports complexes and government offices.

Mexico’s Navy evacuated 850 people from islands off the Baja coast, and deployed almost 3,000 troops for emergency operations. In La Paz, the picturesque capital of Baja California Sur state on the Sea of Cortez, police patrolled closed beaches to keep swimmers out of the whipped-up surf.

In the U.S., the Miami-based hurricane center issued tropical storm and potential flood warnings for Southern California from the Pacific coast to interior mountains and deserts. The San Bernardino County sheriff on Saturday issued evacuation warnings for several mountain and foothill communities ahead of the storm.

And an evacuation advisory for the tourist destination of Santa Catalina Island, 23 miles (37 kilometers) off the Southern California coast, urged residents and beachgoers to leave, while authorities in Los Angeles scrambled to get the homeless off the streets and into shelters.

Across the region, municipalities ran out of free sandbags and grocery shelves emptied out as residents stockpiled supplies. The U.S. National Park Service closed California’s Joshua Tree National Park and Mojave National Preserve to keep visitors from becoming stranded amid flooding.

Major League Baseball rescheduled three Sunday games in Southern California, moving them to Saturday as part of split doubleheaders, and SpaceX delayed the launch of a satellite-carrying rocket from a base on California’s central coast until at least Monday. The company said conditions in the Pacific could make it difficult for a ship to recover the rocket booster.

The White House said President Joe Biden had been briefed on the latest preparedness plans ahead of the hurricane’s turn to the U.S. “I urge everyone, everyone in the path of this storm, to take precautions and listen to the guidance of state and local officials,” he said.

Hilary on Friday had rapidly grown into an exceedingly dangerous Category 4 Major hurricane for a time with top sustained winds of 145 mph (230 kph) at its peak. Its maximum sustained winds initially dropped to 115 mph (185 kph) earlier Saturday as a Category 3 storm, before further weakening to 100 mph (161 kph) as a Category 2.

By late afternoon Saturday, it was still 600 miles (965 kilometers) south-southeast of San Diego, California. Moving north-northwest at 17 mph (28 kph), the storm was expected to turn more toward the north and pick up speed.

Forecasters said the storm was swirling off one of the westernmost spurs on Mexico’s southern Baja peninsula. Loreto, along the peninsula’s eastern coast, recorded wind gusts up to 58 mph (93 kph) on Saturday.

The hurricane was expected to brush past Punta Eugenia on that coast before making a nighttime landfall along a sparsely populated area of the peninsula about 200 miles (330 kilometers) south of the Pacific port city of Ensenada.

Hilary is likely then to rake northward all the way up the peninsula and into Tijuana, before heading to the U.S. in its historic path.

Watson reported from San Diego. Associated Press writers Seth Borenstein in Washington, Maria Verza and Mark Stevenson in Mexico City, John Antczak in Los Angeles, and Eugene Garcia in Newport Beach, California, contributed to this report.