Tropical Storm Hilary was accelerating northward off Mexico’s Baja coast, no longer a hurricane but still packing what forecasters called “life-threatening” rain likely to unleash flooding across a broad region of the western US.

The Mexican cities of Ensenada and Tijuana, directly in the storm’s path, closed all beaches on Sunday and opened a half-dozen shelters at sports complexes and government offices.

Hurricane Centre Director Michael Brennan said Hilary had weakened from a Category 4 hurricane but it was the water, not the wind, that people should watch out for most.

“Rainfall flooding has been the biggest killer in tropical storms and hurricanes in the United States in the past 10 years and you don’t want to become a statistic,” Brennan said in an online briefing from Miami.

One person drowned on Saturday in the Mexican town of Santa Rosalia when a vehicle was swept away in an overflowing stream.

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

Tropical storm and potential flood warnings were posted for the entirety of Southern California, from the Pacific coast to interior mountains and deserts, and as far north as eastern Oregon and Idaho.

Hilary was expected to remain a tropical storm into central Nevada early Monday before dissipating.

Forecasters warned it could dump up to 25 centimetres – a year’s worth of rain for some areas.

California Govorner Gavin Newsom declared a state of emergency.
Hilary is just the latest major climate disaster to wreak havoc across the US, 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 US 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 on 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 on Saturday after his family’s vehicle was swept away by a swollen stream. Four other occupants of the vehicle were rescued.

— AAP