Gustav howled into Cuba’s Isla de Juventud as a monstrous Category 4 hurricane on Saturday while both Cubans and Americans scrambled to flee the path of the fast-growing storm.

Forecasters said it was just short of becoming a top-scale Category 5 hurricane as it powered its way toward the Gulf of Mexico on Sunday, before weakening a little ahead of a likely collision as early as Monday with the U.S. coast.

More than 240,000 Cubans were being evacuated — some hurriedly — as the storm bore down on the nation’s tobacco-rich western tip. Across the Gulf of Mexico, more than a million Americans wary by Hurricane Katrina streamed out of New Orleans and other coastal cities.

Gustav already has killed 81 people by triggering floods and landslides in other Caribbean nations.

Lights flickered in Cuba’s capital as shrieking winds blasted sheets of rain sideways though the streets and whipped angry waves against the famed seaside Malecon boulevard. State television stations went dark several times.

The U.S. National Hurricane Center said Gustav had sustained winds of 150 mph (240 kph) — with higher gusts — as the heart of the storm began hitting Cuba’s outlying island province of Isla de Juventud, where officials cut power to many areas. A Category 5 hurricane has winds above 155 mph (249 kph).

“The rain is not so intense, but there is a lot, a lot of wind,” said Isabel Alarcon from Nueva Gerona, the largest city on the island of 87,000 people. “The officials, they have told us the wind will be bad first but then the rain could cause flooding into the night.”

The government’s AIN news agency said officials were evacuating some 190,000 people from low-lying parts of westernmost Cuba, Pinar del Rio province, where the tobacco for Cuba’s famed cigars is grown. AIN reported that 50,000 already had been evacuated farther east.

Cuba halted all buses and trains to and from Havana where some shuttered stores had hand-scrawled “closed for evacuation” signs plastered to their doors. At those still open, residents formed lines to stock up on bread. Authorities boarded up banks, restaurants and hotels and cars waiting to fill their tanks stretched from gas stations.

“It’s very big and we’ve got to get ready for what’s coming,” said Jesus Hernandez, a 60-year-old retiree who was using an electric drill to reinforce the roof of his rickety front porch.

By Saturday afternoon, Gustav was about 80 miles (135 kilometers) south-southwest of Havana and it was moving northwest near 15 mph (24 kph).

Hurricane force winds extended out 70 miles (110 kilometers) in some places.

The U.S. naval base at Guantanamo, Cuba, was hundreds of miles (kilometers) to the east, out of the storm’s path.

Gustav rolled over the Cayman Islands Friday with fierce winds that tore down trees and power lines while destroying docks and tossing boats ashore, but there was little major damage and no deaths were reported.

Haiti’s Interior Ministry on Saturday raised the hurricane death toll there to 66 from 59 and Jamaica raised its count to seven from four. Gustav also killed eight people in the Dominican Republic early in the week.

Gustav was projected to hit the U.S. Gulf coast roughly around Louisiana on Monday, though forecasters cautioned that the track could vary.

People poured out of New Orleans along highways Saturday and the government announced plans for broader evacuations.

Meanwhile, the hurricane center said Tropical Storm Hanna was projected to near the Turks and Caicos Islands late Sunday or on Monday, then curl through the Bahamas by early next week before possibly threatening Cuba.

As it spun over open waters, Hanna had sustained winds near 50 mph (85 kph) late Saturday afternoon and the hurricane center warned that it could kick up dangerous rip currents along parts of the southeastern U.S. coast.