Hurricane Polo has made landfall along the northern Pacific coast of Mexico, lashing the state of Baja California Sur with life-threatening winds and heavy rain that has already flooded some coastal areas.

Mexican officials said Polo moved ashore just south of the surfing and fishing village of Las Barrancas bringing maximum sustained winds of 110 mph (175 km/h).

Polo is moving northeast and on the forecast track, its core is predicted to continue passing over Baja California Sur before moving inland over the southern part of the Mexican state of Sonora later on Tuesday.

Residents in threatened areas have been encouraged to seek shelter.

Shopkeeper María Palomino, 57, spent the night at a high school which has been turned into a temporary shelter. "If something happens, it's better to come to the shelter," she told AFP news agency.

A whale-watching and fishing guide who was boarding up the facade of his home told AFP the storm was "coming with full force".

The US-based National Hurricane Center (NHC) said that while Polo was expected to weaken as it moved over the Baja California peninsula, it was forecast to still be at hurricane strength when it makes its second landfall in mainland Mexico.

Meteorologists said Polo could dump between 6 and 12 inches (150-300mm) of rain across parts of Baja California Sur, which they warned could produce life-threatening flooding and mudslides, especially in areas of steep terrain.

The NHC said a storm surge was also expected to produce significant coastal flooding in areas of onshore winds. "Near the coast, the surge will be accompanied by large and destructive waves," it said in an update.

Even before Polo made landfall, residents said there were power cuts in Baja California Sur.

US media reported some flooding in the fishing town of Puerto San Carlos and the Associated Press said waves crested sea barriers in the area, where many residents had been evacuated due to the threat.

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Meteorologists said dangerous surf and rip currents were likely to continue along portions of the north-western coast of Mexico and Baja California for the next day or so.

The south of the peninsula is popular with tourists and acts as a base for surfers, sport fishers, and whale watchers.

In Cabo San Lucas, famous for its natural rock arch, authorities had restricted access to the beaches on Monday.

Polo has been slowly moving towards Mexico's coast line for days.

Meteorologists said it was being fuelled by extremely warm waters caused by the El Niño climate phenomenon, which has led to a more active hurricane season in Pacific waters.

As Polo moves north-east, it is expected to also affect the US, sending a surge of tropical moisture northwards for the next few days leading to excessive rainfall and flash flooding.

Rain has already been falling across Arizona and California but the remains of Polo and another hurricane - named Odalys - will become absorbed into that weather system, boosting the amount of rainfall. These fronts will push eastwards across the southern plains.

Some spots could see as much as 6 or 7 inches of rainfall by Thursday.

States affected include Arizona, New Mexico, Colorado and Utah into Tuesday.