Some 20,000 tourists and residents were evacuated earlier in coastal towns in Nayarit and Jalisco states ahead of the storm's impact.

National Weather Service forecasters have called Kenna "an extremely dangerous system," which could cause considerable wind damage, flooding and mudslides.

A hurricane warning remains in effect for the southwestern coast of Mexico from Mazatlan southward to La Fortuna

In Miami, the US weather service said that "rainfall accumulations of 15-25 cm (6-10 inches) with isolated higher amounts especially in mountainous areas can be expected in association with Kenna.

"These rains could cause life-threatening flash floods and mud slides," it warned.

"Coastal storm surge flooding of 1.8-3 m (6-10 feet) above normal tide levels along with large and dangerous battering waves can be expected near and to the south of where the center crosses the coast," it added.

Trinidad Lopez of civil defense in Jalisco state said the Nayarit town of San Blas was being battered, and that authorities were treating the storm -- a Category Four (of a maximum five) on the Saffir-Simpson scale -- as a major threat.

In the tourist town of Puerto Vallarta, more than 4,000 people were evacuated from the old town area. The seafront promenade is completely under water, authorities said.

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