Locals and tourists flee as Hurricane Willa bears down on Mexico's Pacific coast

Mexico is bracing for the devastating impact of Hurricane Willa, which is heading for its Pacific coast where it is expected to hit with potentially deadly wind and flooding.

The Category 4 hurricane - downgraded after earlier reaching Category 5 - was on course to hit land somewhere around the resort town of Mazatlan on Tuesday afternoon or evening, said the US National Hurricane Centre.

Willa now has maximum sustained winds of 250 kilometres (155 miles) per hour, the NHC said in its latest update.

Despite weakening slightly, "Willa is expected to be a dangerous major hurricane when it reaches the coast of Mexico," it said.

Willa is expected to dump 15 to 30 centimeters (six to 12 inches) of rain on parts of Sinaloa, Nayarit and Jalisco states, with some areas getting up to 45 centimeters.

"This rainfall will cause life-threatening flash flooding and landslides," the NHC warned.

The centre said large storm swells off the coast were also "likely to cause life-threatening surf and rip current conditions".

The hurricane was located about 175 kilometres west-southwest of Cabo Corrientes, churning north at 13 kilometres per hour.

It was on track to sweep past the Marias islands, where Mexico has a federal prison, early on Tuesday.

The interior ministry did not immediately respond to questions on whether it planned to evacuate the inmates housed there.

State of alert

Sinaloa, Nayarit and Jalisco declared a state of alert and cancelled school state-wide Monday as rain and heavy waves began to set in.

In the resort town of Puerto Vallarta, Aristoteles Sandoval, governor of Jalisco, ordered the evacuation of hotels and coastal areas. Shelters were opened on higher ground to accommodate evacuees.

"This could become a phenomenon with very destructive consequences. We will probably have to start evacuating (other) communities," he said.

"We're already prepared with food and shelters, state and local emergency services are prepared, the health ministry is ready, the water authority is working on water and sanitation, the army and marines are ready to help with search and rescue."

In Mazatlan, top resort hotels were virtually empty, but a handful of hardy tourists were determined not to let the hurricane ruin their vacations.

Tour operators and fishermen meanwhile raced to tie down their boats ahead of the storm.

Derailed train

In Michoacan state, heavy rain caused a freight train to derail in the town of La Goleta, injuring at least two workers for the Kansas City Southern rail line, authorities said.

Elsewhere, Tropical Storm Vicente - with maximum sustained winds of 65 kilometres per hour - was expected to bring heavy rainfall and flooding over Mexico's south and southwest, also making landfall on Tuesday.

Mexico's Pacific coast has already been hit by deadly storms and rains this hurricane season.

In September, at least 15 people were killed when flash floods hit the states of Sinaloa and Michoacan. Last week, 11 more people died in Oaxaca, including seven children.