Hurricane Patricia, one of the most powerful storms on record, struck Mexico's Pacific coast on Friday with destructive winds that tore down trees, moved cars and forced thousands of people to flee homes and beachfront resorts.

Hours after making landfall, the storm weakened but still packed winds of  210 km per hour. There were no reported casualties and officials said the damage might not be as catastrophic as feared.

The storm slammed into a stretch of sparsely populated coastline near the popular beach getaway of Puerto Vallarta, where 15,000 tourists were evacuated to avoid the rain and winds of at the speed of 266 kms/hour.

"The winds are really strong. It's amazing, even the cars are moving," said Laura Barajas, a 30-year-old hotel worker from the major cargo port of Manzanillo.

Visitors and residents weathered the Category 5 hurricane in emergency shelters hoping it would not do as much damage as the last storm of this magnitude, Typhoon Haiyan, which killed thousands of people in the Philippines in 2013.

The U.S. National Hurricane Center forecast Patricia would move deep inland and could dissipate on Saturday as its winds will be sapped by the mountains of western Mexico.

In Puerto Vallarta, the heart of a string of resorts that range from low-end mega hotels to exclusive villas attracting tech billionaires and pop stars, loudspeakers had blared orders to evacuate hotels ahead of Patricia's arrival. The streets emptied as police sirens wailed in anticipation of Patricia, which gathered strength suddenly on Thursday night.

U.S. weather experts said Patricia was the strongest storm yet registered in the Western Hemisphere, and said the unprecedented hurricane could have a catastrophic impact.

"Whichever way you turn, there's debris," said Juan Michel, 36, a hotel manager in the resort of Barra de Navidad, who was taking cover from Patricia with 13 others. "We've never seen anything like this", he added.

Writing from 401 kms above Earth on the International Space Station, U.S. astronaut Scott Kelly tweeted an imposing image of the giant storm along with the message: "Stay safe below, Mexico."

Patricia began the day blowing winds of up to 322 kms/hour but was weakening noticeably as it hit the coast.

U.S. President Barack Obama said the United States was standing by Mexico.