Tropical storm Hilary batters California, causes deadly flooding in Mexico

Deadly floodwaters inundated streets across Mexico's arid Baja California on Sunday as tropical storm Hilary moved ashore, carrying torrential rain into Southern California, with concerns mounting that flash floods could strike in places as far north as Idaho that rarely get such heavy rain.

Forecasters said Hilary was the first tropical storm to hit Southern California in 84 years, bringing the potential for flash floods, mudslides, isolated tornadoes, high winds and power outages.

Hilary made landfall along the Mexican coast in a sparsely populated area about 250 kilometres south of Ensenada, on a path to hit mudslide-prone Tijuana Sunday evening, threatening the improvised homes that cling to hillsides just south of the U.S. border.

At least 9 million people were under flash-flood warnings as heavy rain fell across normally sunny Southern California ahead of the brunt of the storm. Desert areas were especially susceptible along with hillsides with wildfire burn scars, forecasters warned.

Mud spilled onto highways, water overwhelmed drainage systems and tree branches fell in places from San Diego to Los Angeles. The weather service said tornadoes were possible Sunday afternoon in eastern San Diego County.

Southern California got another surprise in the afternoon as an earthquake with a preliminary magnitude of 5.1 hit near Ojai, about 130 kilometres northwest of downtown Los Angeles, according to the U.S. Geological Survey. It was felt widely and was followed by smaller aftershocks. There were no immediate reports of major damage or injury, according to a dispatcher with the Ventura County Sheriff's Office.

Hilary could wallop other western states with once-in-a-century rains, with a good chance of it becoming the wettest known tropical cyclone to douse Nevada, Oregon and Idaho. Hilary was expected to remain a tropical storm into central Nevada early Monday before dissipating.

By 2 p.m. PT, Hilary was 180 kilometres south-southeast of San Diego, the National Hurricane Center reported. The storm had maximum sustained winds of 95 km/h and was moving northwest at nearly 41 km/h.

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 a 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 that nation's worst fire season on record.

The Mexican cities of Ensenada and Tijuana closed all beaches and opened a half-dozen shelters at sports complexes and government offices.

One person drowned Saturday in the Mexican town of Santa Rosalia when a vehicle was swept away in an overflowing stream. Rescue workers saved four other people, said Edith Aguilar Villavicencio, the mayor of Mulege township.

Mexican army troops fanned out across Mulege, where some of the worst damage occurred Saturday on the eastern side of the Baja Peninsula. Soldiers used bulldozers and dump trucks to help clear tons of boulders and earth clogging streets and roads that were turned into raging torrents a day earlier.

Power lines were toppled in many places, and emergency personnel were working to restore power and reach those cut off by the storm.

California Gov. Gavin Newsom declared a state of emergency. The Federal Emergency Management Agency said it has officials inside California's emergency preparedness office and teams on standby with food, water and other help.