Hurricane Polo made landfall in the southern half of Mexico's Baja California peninsula in the early hours of Tuesday with gusts of up to 200 km/h (125 mph).
Authorities expected life-threatening hurricane conditions to continue across Baja California Sur for several hours, while weather conditions were expected to deteriorate in the south of the mainland state of Sonora.
Polo hit land as a category 2 hurricane south of Las Barrancas, halfway down the state's west coast, a zone far less populated than the Los Cabos resort corridor at the southern tip of the peninsula.
Mexico's National Weather Service said it had brought sustained winds of 150 to 170 km/h with gusts of 180 to 200 km/h and waves 7 to 9 meters high.
The storm was expected to dump 6 to 12 inches (15 to 30 cm) of rain across Baja California Sur, with a risk of life-threatening flooding and mudslides, according to the US National Hurricane Center.
Polo is still expected to be a hurricane at its second landfall in mainland Mexico, after crossing the Gulf of California.
Both Mexican authorities and the NHC urged residents to remain safe indoors through the morning, either at their homes or in temporary shelters opened up in high-risk areas.
Residents of the towns in Polo's path packed supermarkets over the weekend to buy essential products while business owners boarded up doors and windows in anticipation of the storm.
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