Cat 1 Hurricane Hilary Expected to Hit Southern California With Heavy Rain Sunday Afternoon After Slamming Baja With Flash Floods

Heavy rain from a weakened but still dangerous Hurricane Hilary was expected in Southern California early Sunday afternoon after streams and rivers in Baja California in Mexico exploded from their banks Saturday evening.

Videos posted by local officials showed waters raging through the streets of Santa Rosalia in the middle of the Baja peninsula Saturday as Californians braced for their own visit from Hilary, which weather officials said could bring "rare and dangerous storms."

One person drowned in Santa Rosalia when the vehicle he was in was swept away in an overflowing stream, the Associated Press reported.

Rescue workers managed to save four other people, said Edith Aguilar Villavicencio, the mayor of Mulege township.

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

Elizabeth Adams, a meteorologist at the National Weather Service San Diego office, said rain could fall up to 3 inches an hour across Southern California's mountains and deserts, from late Sunday morning into the afternoon. The intense rainfall during those hours could cause widespread and life-threatening flash floods.

The forecast prompted authorities to issue an evacuation advisory for Santa Catalina Island, urging residents and beachgoers to leave the tourist destination 23 miles off the coast. Evacuations were also ordered Saturday night for the communities of San Bernardino County forecast to be in Hilary's path.

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

There will likely be "damaging wind gusts," especially at higher elevations, in the area, and swells along the coast, Greg Postel, a hurricane and storm specialist at the Weather Channel, told CBS News.

“California has thousands of people on the ground working hand-in-hand with federal and local personnel to support communities in Hurricane Hilary’s path with resources, equipment and expertise," Newsom said in a statement.

"We’re mobilizing all of government as we prepare and respond to this unprecedented storm," he added.

The storm was picking up speed as it headed north, clocking in at 21 mph Sunday morning. It was about 30 miles southeast of Punta Eugenia, Mexico.

Hilary is forecast to be a tropical storm by the times it reaches California.

But it is still expected to carry a high risk of flash flooding that could include "landslides, mudslides and debris flow" in mountains and deserts in Southern California, according to the National Weather Service in San Diego.

Late Friday Hilary clocked in as a Category 4 storm, but slipped to Category 1 by Saturday night. It was packing winds of 85 miles per hour that officials warned could still be "catastrophic."