An impending storm could cause “life-threatening” flooding in Mexico and the south-western United States

Hurricane Hilary is moving towards Mexico’s Pacific coast with winds of up to 130mph (215km/h). It is expected to make landfall later on Saturday.

Forecasters say it will then lose speed and become a tropical storm, moving towards southern California.

It would be the first tropical storm to hit California in more than 80 years.

In its first-ever tropical storm warning for the state, the National Hurricane Service said “catastrophic and life-threatening flooding” were likely in the Mexican state of Baja California and the south-west US over the coming two days.

The Federal Emergency Management Agency had “pre-positioned personnel and supplies in the region”, US President Joe Biden said on Friday. “I urge everyone in the path of the storm to take precautions and listen to the guidance from state and local officials.”

Rainfall could reach 10in (25cm) in some areas, leading to “significant and rare” impacts for parts of southern California and southern Nevada, the National Weather Service (NWS) said.

In San Diego, the NWS issued a warning for the “high potential” of flash flooding. Nearly 26 million people in the south-western US were under flood watch.

As of 12:00 GMT on Saturday, the hurricane was roughly 300 miles (500km) west of Baja California’s southern edge, the NHS said.

Parts of Mexico are under a tropical storm watch, and its government has placed 18,000 soldiers on standby to assist in rescue efforts.

As the storm bears down, Major League Baseball has rescheduled three games in southern California, while SpaceX delayed the launch of a rocket from its base on the central California coast until at least Monday.

The National Park Service also closed Joshua Tree National Park and Mojave National Preserve, both in California, to prevent visitors from being stranded in the event of flooding.

Local officials in cities across the region, including in Arizona, are offering sandbags to residents seeking to safeguard their properties against potential floodwaters.

Hurricanes and tropical storms are somewhat common in Mexico. But the last time a tropical storm made landfall in southern California was in Long Beach in 1939.

Experts say the abnormal weather events plaguing the US – and several areas across the globe – are being influenced by human-caused climate change.

In the wake of the hottest month on record, July 2023, according to Nasa, the deadliest wildfire in modern US history spread across Hawaii on 8 August, killing at least 111 people.

The damage was escalated by hurricane winds passing through the area.