Gustav roared into the oil-rich Gulf of Mexico as a ferocious Category 4 hurricane Sunday after destroying homes and roads in Cuba. The mayor of New Orleans ordered residents to flee the "storm of the century" by morning.
The U.S. National Hurricane Center said Gustav weakened slightly over Cuba but was expected to regain strength as it moves over the warm waters of the Gulf of Mexico and toward the U.S. Coast, possibly becoming a top-scale Category 5 hurricane on Sunday.
Forecasters said Gustav was just short of Category 5 strength when it made landfall Saturday on mainland Cuba near the community of Los Palacios in Pinar del Rio — a region that produces much of the tobacco used to make the nation's famed cigars.
At least 300,000 people were evacuated from Gustav's path as screaming 140 mph (220 kph) winds toppled telephone poles and fruit trees, shattered windows and tore off the tin roofs of homes.
Cuban Civil defense chief Ana Isla said there were "many people injured" on Isla de la Juventud, an island of 87,000 people south of the mainland, but no reports of deaths. She said nearly all the island's roads were washed out and some regions were heavily flooded.
"It's been very difficult here," she said on state television.
Forecasters said Gustav could hit Category 5 — the highest on the Saffir-Simpson scale used to rate tropical cyclones — with winds above 155 mph (249 kph) on Sunday. It was expected to make landfall Monday along the U.S. Gulf coast, and authorities issued a hurricane watch from eastern Texas to the Alabama-Florida border.
More than 1 million Americans made wary by Hurricane Katrina took buses, trains, planes and cars as they streamed out of New Orleans and other coastal cities, where Katrina killed about 1,600 people in 2005.
Mayor Ray Nagin of New Orleans, which was devastated three years ago by Hurricane Katrina, issued a mandatory evacuation order beginning 8:00 a.m. and warned that anyone found off their own property after it takes effect can be arrested.
Nagin called Gustav the "mother of all storms" and told residents to "get out of town. This is not the one to play with."
City officials began putting an estimated 30,000 elderly, disabled and poor residents on buses and trains for evacuation.
Gustav already has killed 81 people by triggering floods and landslides in Haiti, the Dominican Republic and Jamaica.
Cuba's top meteorologist, Jose Rubiera, said the storm brought hurricane-force winds to much of the western part of Havana, where power was knocked out as winds blasted sheets of rain sideways though the streets and whipped angry waves against the famed seaside Malecon boulevard.
Felled tree branches and large chunks of muddy earth littered roads that were largely deserted overnight.
In tourist-friendly Old Havana, heavy winds and rain battered crumbling historic buildings. There were no immediate reports of major damage, but a scaffolding erected against a building next to the Plaza de Armas was leaning at a dangerous angle.
Tourist Lidia Morral of Barcelona, Spain, said Gustav forced officials to close beaches the couple wanted to visit earlier this week in Santiago, on the island's eastern tip. The storm also prevented them from catching a ferry from Havana to the Isla de la Juventud on Saturday.
"It's been following us all over Cuba, ruining our vacation," said Morral, who was in line at a travel agency, trying to make other plans. "They have closed everything, hotels, restaurants, bars, museums. There's not much to do but wait."
At 2:00 a.m. EDT Sunday, the hurricane center said Gustav was centered about 485 miles (780 kilometers) southeast of the mouth of the Mississippi River and was moving northwest near 15 mph (24kph). The storm had sustained winds of 135 mph (220 kph), with higher gusts.
In the Gulf of Mexico, where about 35,000 people work staffing offshore rigs and production facilities, among other tasks, oil companies wrapped up evacuations in preparation for the storm. More than three-fourths of the Gulf's oil production and nearly 40 percent of its natural gas output were shut down on Saturday, according to the U.S. Minerals Management Service, which oversees offshore activity.
The U.S. Gulf Coast accounts for about 25 percent of domestic oil production and 15 percent of natural gas output, according to the MMS. The Gulf Coast also is home to nearly half the nation's refining capacity.
Analysts say prolonged supply disruptions could cause a sudden price uptick for gasoline and other petroleum products.
Meanwhile, 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 strengthened slightly and had sustained winds near 55 mph (95 kph) early Sunday. The hurricane center warned that it could kick up dangerous rip currents along parts of the southeastern U.S. coast.
The U.S. State Department urged Americans to be aware of the risks caused by Hanna to people traveling to the Bahamas and the Turks and Caicos Islands. It urged U.S. citizens lacking safe shelter to consider leaving while flights are still available.