The hurricane was churning about 75 km southwest of Cuba's capital Havana late on Wednesday, lashing the capital city of nearly two million people with driving rain and violent wind gusts.
The Miami-based National Hurricane Center warned of a "life-threatening storm surge, damaging hurricane-force winds and flash flooding" across much of western Cuba.
The region, including Havana, remained under a hurricane warning.
...RAFAEL MAKES LANDFALL IN THE CUBAN PROVINCE OF ARTEMISA at 4:15 PM EST...— National Hurricane Center (@NWSNHC) Major Hurricane #Rafael Advisory 13: 4:00 PM EST Wednesday November 6, 2024Full forecast details at: https://t.co/TeLLMFmCkN pic.twitter.com/ZglhbfAXNwNovember 6, 2024
Cuba's state-run grid operator UNE said the high winds had caused the nation's electrical system to collapse.
State-run television reported the entire population of 10 million people was without electricity - the second such incident in less than a month on the island.
Conditions had deteriorated quickly by mid-afternoon in Havana, east of the storm's predicted track, and wind and rain had already downed trees and powerlines on city streets.
The capital is especially vulnerable to a hurricane strike and flooding, with antiquated, densely packed housing and decrepit infrastructure.
Police cruisers with loudspeakers began circling central neighbourhoods encouraging people to shelter in place ahead of the storm.
Schools and public transportation in the city were suspended until further notice, and authorities grounded flights at both Havana's Jose Marti International Airport as well as at the popular beach resort at Varadero through to Thursday.
Police are encouraging people in Havana to shelter in place. (AP PHOTO)
Officials said they had evacuated more than 100 Canadian tourists from Cayo Largo, another popular beach destination off southwestern Cuba.
The farm provinces of Artemisa and Pinar del Rio - home to the prized tobacco used in Cuba's famous hand-rolled cigars - were expected to take a near direct hit as Rafael made landfall on the Caribbean island.
Farmers had moved to protect 8000 metric tonnes of tobacco in the area, Agriculture Minister Ydael Pérez Brito said, as well as ripening fruits and vegetables.
The timing could not be worse for the Communist-run island, which in October suffered another total collapse of its national electric grid, leaving the nation without power for several days.
Hurricane Oscar made landfall in far eastern Cuba around the same time as the blackout, throwing a one-two punch that has sapped precious resources in a nation suffering from severe shortages of food, fuel and medicine.
Rafael grazed the Cayman Islands as a Category 1 cyclone overnight before increasing in less than 24 hours to a much more powerful Category 3 storm off Cuba's southwestern shore.
Forecasters predict Rafael will spin off towards the western Gulf of Mexico later this week, though the track remains uncertain, the NHC said.