Hurricane Hilary headed for Mexico's Baja California with “life-threatening and potentially catastrophic” rain and flash flooding, while officials as far north as Los Angeles scrambled to get the homeless off the streets, set up shelters and prepare for evacuations.

Hilary is expected to plow into the Mexican peninsula sometime Sunday and then surge northward and enter the history books as the first tropical storm to hit Southern California in 84 years by late Sunday or Monday.

The U.S. National Hurricane Center issued a tropical storm watch for a wide swath of Southern California from the Pacific coast to interior mountains and deserts. Officials talked of evacuation plans for California’s Catalina Island.

“I don’t think any of us — I know me particularly — never thought I’d be standing here talking about a hurricane or a tropical storm,” said Janice Hahn, chair of the Los Angeles County Board of Supervisors.

After rapidly gaining power early Friday, Hilary slowed some later in the day but remained a major Category 4 hurricane late Friday with maximum sustained winds of 130 mph (215 kph), down from 145 mph (230 kph).

Late Friday, the storm was centered about 285 miles (460 kilometers) southwest of the southern tip of the Baja peninsula. It was moving north-northwest at 13 mph (20 kph) and was expected to turn more toward the north.

The latest forecast track pointed to Hilary making landfall along a sparsely populated area of the Baja peninsula at a point about 200 miles (330 kilometers) south of the Pacific port city of Ensenada.

It is then expected to continue northward, raising fears that its heavy rains could cause dangerous flooding in the border city of Tijuana, where many homes in the city of 1.9 million cling precariously to steep hillsides.

Mayor Montserrat Caballero Ramirez said the city was setting up four shelters in high-risk zones and warning people in risky zones.

“We are a vulnerable city being on one of the most visited borders in the world and because of our landscape,” she said.

Concern was rising in the US

The National Park Service closed Joshua Tree National Park and Mojave National Preserve to keep people from becoming stranded amid flooding. Cities across the region, including in Arizona, were offering sandbags to safeguard properties against floodwaters. Major League Baseball rescheduled three Sunday games in Southern California, moving them to Saturday as part of split-doubleheaders,

Deputies with the Los Angeles Sheriff’s Department took to the road to urge homeless people living in riverbeds to seek shelter. Authorities in the city were arranging food, cots and shelters for people who needed them.

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.

President Joe Biden said the Federal Emergency Management Agency had pre-positioned staff and supplies in the region.

“I urge everyone, everyone in the path of this storm, to take precautions and listen to the guidance of state and local officials,” Biden told reporters Friday at Camp David, where he is meeting with the leaders of Japan and South Korea.

Officials in Southern California were re-enforcing sand berms, built to protect low-lying coastal communities against winter surf, like in Huntington Beach, which dubs itself as “Surf City USA.”

In nearby Newport Beach, Tanner Atkinson waited in a line of vehicles for free sandbags at a city distribution point.

“I mean a lot of people here are excited because the waves are gonna get pretty heavy,” Atkinson said. “But I mean, it’s gonna be some rain, so usually there’s some flooding and the landslides and things like that.”

Some schools in Cabo San Lucas were being prepared as temporary shelters, and 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. Schools were shut down in five municipalities.

It was increasingly likely that Hilary would reach California early Monday while still at tropical storm strength, though widespread rain was expected to begin as early as Saturday, the National Weather Service’s San Diego office said.

Hurricane officials said the storm could bring heavy rainfall to the southwestern United States, dumping 3 to 6 inches (8 to 15 centimeters) in places, with isolated amounts of up to 10 inches (25 centimeters), in portions of southern California and southern Nevada.

“Two to three inches of rainfall in Southern California is unheard of” for this time of year, said Kristen Corbosiero, a University of Albany atmospheric scientist who specializes in Pacific hurricanes. “That’s a that’s a whole summer and fall amount of rain coming in probably 6 to 12 hours.”

The region could face once-in-a-century rains and there is a good chance Nevada will break its all-time rainfall record, said meteorologist Jeff Masters of Yale Climate Connections and a former government in-flight hurricane meteorologist.