Hurricane Willa, an extremely dangerous Category 4 storm, has weakened slightly as it veers toward popular tourist resorts on Mexico's Pacific coast, prompting government warnings for people to leave high-risk areas and take cover.
Mexican authorities have urged residents to evacuate their homes for temporary shelters, closed ports, cancelled classes and suspended beachside and marine activities.
The storm was due to come ashore after lunch on Tuesday (local time) just south of Mazatlan, a popular beach resort in the northwestern state of Sinaloa. Several other tourist destinations in the neighbouring state of Nayarit also lie near to the storm's path.
Willa, which earlier in the day had been a Category 5 on the five-step Saffir-Simpson scale, was blowing maximum sustained winds of near 240km/h by evening with higher gusts, the US National Hurricane Center (NHC) said.
Complete power outages, damage to roofs and even the foundations of buildings that are up to 500 metres from the coastline were possible, Mexico's National Meteorological Service (SMN) said.
In Sinaloa, Tuesday classes were cancelled in towns stretching more than 200km across the state, including Mazatlan, as well as in all of Nayarit.
Alberto Hernandez, head of the SMN, said the storm would probably be a Category 4 or 3 hurricane when it reached land, and could cause waves several metres high.
It could also lead to the formation of waterspouts in front of the coast of Puerto Vallarta, the SMN said, referring to another beach resort in the state of Jalisco next to Nayarit.
Australian Associated Press