Hurricane Sandy raged through the Bahamas early Friday after leaving 21 people dead across the Caribbean, following a path that could see it blend with a winter storm and reach the U.S. East Coast as a super-storm next week.

Sandy knocked out power, flooded roads and cut off islands in the storm-hardened Bahamas as it swirled past Cat Island and Eleuthera, but authorities reported no deaths in the scattered archipelago.

"Generally people are realizing it is serious," said Caroline Turnquest, head of the Red Cross in the Bahamas, who said 20 shelters were opened on the main island of New Providence.

Sandy, which weakened to a category 1 hurricane Thursday night, caused havoc in Cuba early in the day, killing 11 people in eastern Santiago and Guantanamo provinces as its howling winds and rain toppled houses and ripped off roofs. Authorities said it was Cuba's deadliest storm since July 2005, when category 5 Hurricane Dennis killed 16 people and caused $2.4 billion in damage.

Sandy also killed one person while crossing Jamaica on Wednesday and 10 in Haiti, where heavy rains from the storm's outer bands caused flooding in the impoverished and deforested country.

Late Thursday, the hurricane's center was about 185 miles (300 kilometers) east-southeast of Freeport, Bahamas. The storm had maximum sustained winds of 90 mph (150 kph) and was moving north-northwest at 13 mph (20 kph).

Forecasters warned that Sandy will likely mix with a winter storm to create a monster storm in the eastern U.S. next week whose effects will be felt along the entire Atlantic Coast from Florida to Maine and inland to Ohio.

Sandy, which crossed Cuba and reached the Bahamas as a category 2 hurricane, was expected to maintain its category 1 storm status for the next several days.

In the Bahamas, power was out on Acklins Island and most roads there were flooded, government administrator Berkeley Williams said.

On Ragged Island in the southern Bahamas, the lone school was flooded.

"We have holes in roofs, lost shingles and power lines are down," said Charlene Bain, local Red Cross president. "But nobody lost a life, that's the important thing."

Steven Russell, an emergency management official in Nassau, said that docks on the western side of Great Inagua island had been destroyed and that the roof of a government building was partially ripped off.

Sooner Halvorson, a 36-year-old hotel owner from Colorado who recently moved to the Bahamas, said she and her husband, Matt, expected to ride out the storm with their two young children, three cats, two dogs and a goat at their Cat Island resort.

"We brought all of our animals inside," she said, though she added that a horse stayed outside. "She's a 40-year-old horse from the island. She's been through tons of hurricanes."

On Great Exuma island, guest house operator Veronica Marshall supplied her only customer with a flashlight and some food before Sandy bore down. She said she was confident that she and her business would make it through intact.

"I'm 73 years old and I've weathered many storms," she said.

Tropical storm conditions were possible for Florida's southeastern coast, the Upper Keys and Florida Bay by Friday morning.

Hurricane Sandy was expected to churn through the central and northwest Bahamas by Friday afternoon and then head northward off the U.S. coast.

With storm conditions projected to hit New Jersey with tropical storm-force winds Tuesday, there was a 90 percent chance that most of the U.S. East Coast would get steady gale-force winds, flooding, heavy rain and maybe snow starting Sunday and stretching past Wednesday, U.S. forecaster Jim Cisco said.

In an announcement at the end of Cuba's Thursday night newscast, Cuban authorities said the island's 11 dead included a 4-month-old boy who was crushed when his home collapsed and an 84-year-old man in Santiago province.

Santiago, Cuba's second largest city near the eastern tip of the island, was spared the worst of the storm, which also slammed the provinces of Granma, Holguin and Las Tunas.

There were no reports of injuries at the U.S. naval base at Guantanamo Bay in Cuba, but there were downed trees and power lines, said Kelly Wirfel, a base spokeswoman. Officials canceled a military tribunal session scheduled for Thursday for the prisoner charged in the 2000 attack on the Navy destroyer USS Cole.

In Haiti, Joseph Edgard Celestin, a spokesman for the civil protection office, said the country's death toll stood at nine, including three people who died while trying to cross storm-swollen rivers in southwestern Haiti. He did not provide specifics of how other people died.

Officials reported flooding across Haiti, where many of the 370,000 people still displaced by the devastating 2010 earthquake scrambled for shelter. More than 1,000 people were evacuated from 11 quake settlements, according to the International Organization for Migration.

Sandy was blamed for the death of an elderly man in Jamaica.