U.S. weather experts warned that despite the weakening that hurricane Hilary started to show – as it heads towards the Pacific Coast of Mexico and California – it could still cause "life-threatening" floods.

With wind speeds recorded at 140 kilometers per hour, experts downgraded the hurricane to a Category 1 storm.

Heavy rains hit parts of the Baja California Peninsula in Mexico and the southwestern United States overnight.

One person died after being swept away while crossing a waterway in Baja California.

Hurricane Hilary is expected to weaken further to become a tropical storm before reaching Southern California. This will be the first tropical storm to hit the U.S. state in over 80 years.

The U.S. National Hurricane Center, in its latest update at 6 a.m. GMT on Sunday, said the hurricane was located 145 kilometers south of the westernmost point in Baja California at Punta Eugenia.

The Center added that Hilary "will move to a point near the central western coast of the Baja California Peninsula" on Sunday morning and then move across Southern California on Sunday afternoon.

The Associated Press quoted John Cangialosi, a senior hurricane specialist at the U.S. National Hurricane Center, stating last Saturday: "It appears Hilary is weakening rapidly."

He added: "The eye of the hurricane and the cloud tops in the eyewall are filling while the rain temperatures have been rising over the past several hours."

Hurricane Hilary had previously been classified as a powerful Category 3 storm with wind speeds reaching 209 kilometers per hour.

The Center predicted rainfall could reach up to 25 centimeters in some areas of Southern California and Southern Nevada. It also noted that "severe to catastrophic" flooding is expected.

In San Diego, the National Weather Service earlier issued a warning of "increasing chances" of flash floods. Nearly 26 million people in the southwestern United States were anticipating flooding in their areas.

U.S. President Joe Biden stated last Friday that the Federal Emergency Management Agency (FEMA) "has deployed teams and supplies to the region as a precautionary measure."

He added, "Everyone in the storm's path should take necessary precautions and heed the guidance of state and local officials."

Mexico is bracing for tropical storm conditions in parts of the country, with the government putting 18,000 soldiers on standby to assist in rescue efforts.

As the storm approaches, Major League Baseball rescheduled three games in Southern California, while SpaceX postponed a rocket launch 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 any visitors from being harmed if they get stranded in those parks due to potential flooding.

Local officials in cities throughout the area, including in Arizona, are providing sandbags to residents seeking to protect their homes from flooding waters should they occur.

Hurricanes and tropical storms are relatively common phenomena in Mexico. However, the last time a tropical storm made landfall in Southern California was in Long Beach in 1939.

Experts say that the abnormal weather changes affecting the United States – and many areas around the world – are influenced by human-caused climate change.

Following the hottest month on record, July 2023, the deadliest wildfire in modern U.S. history erupted in Hawaii on August 8, resulting in at least 111 fatalities.