Tropical Storm Hilary swirled northward Sunday just off the coast of Mexico’s Baja California peninsula, no longer a hurricane but still carrying so much rain that forecasters said “catastrophic and life-threatening” flooding is likely across a broad region of the southwestern U.S.

As of 8 a.m. Pacific time, Hilary was located about 220 miles south-southeast of San Diego, the National Hurricane Center reported. Hilary had maximum sustained winds of 70 mph and was moving northwest at 25 mph.

The Mexican cities of Ensenada and Tijuana remained directly in the tropical storm’s path, and meteorologists warned that despite weakening, the storm remained treacherous.

One person drowned Saturday in the Mexican town of Santa Rosalia, on the peninsula’s eastern coast, when a vehicle was swept away in an overflowing stream. Rescue workers managed to save four other people, said Edith Aguilar Villavicencio, the mayor of Mulege township.

It was not immediately clear whether officials considered the fatality related to the hurricane, but video posted by local officials showed torrents of water coursing through the town’s streets.

Forecasters said the storm was still 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. Authorities issued an evacuation advisory for Santa Catalina Island, urging residents and beachgoers to leave the tourist destination 23 miles off the coast.

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.

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.

Hilary is just 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 ravaged the historic town of Lahaina, making it the deadliest U.S. wildfire in more than a century. Firefighters in Canada are battling blazes during the nation’s worst fire season on record.

Hilary left a long string of washed-out highways and roads up and down the Baja peninsula in its wake Sunday. Some of the worst damage occurred in the coastal towns of Mulege and Santa Rosalia, on the east side of the peninsula, where a man died Saturday after his family’s vehicle was swept away by a swollen stream. Four other occupants of the vehicle were rescued. Power lines were toppled in many places, and emergency personnel were working to restore power and reach those cut off by the storm.

In California, evacuation warnings were issued for Santa Catalina Island, urging residents and beachgoers to leave the tourist destination for the mainland, and for several mountain and foothill communities in San Bernardino County. Orange County sent an alert for anyone living in a wildfire burn scar in the Santa Ana Mountains’ Silverado and Williams canyons.

Los Angeles authorities scrambled to get the homeless off the streets and into shelters, and officials ordered all state beaches in San Diego and Orange counties closed.

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

“I urge everyone, everyone in the path of this storm, to take precautions and listen to the guidance of state and local officials,” President Joe Biden said.

Meanwhile, one of several budding storm systems in the Atlantic Ocean became Tropical Storm Emily on Sunday, according to the National Hurricane Center. It was located far from land, moving west in the open ocean.

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

Editor’s note: This story has been updated with more current information, including that Hilary was downgraded from a hurricane to a tropical storm.