PORT-AU-PRINCE, Haiti (AP) -- Hurricane Gustav barreled into Haiti on Tuesday, toppling trees, dumping rain and sending global fuel prices soaring on fears the storm could become "extremely dangerous" when it reaches the Gulf of Mexico.
The hurricane roared ashore with top sustained winds near 90 mph at about 1 p.m. EDT, 10 miles west of the city of Jacmel and 40 miles from the capital of Port-au-Prince. Heavy rains pelted the area, bending palm trees and kicking up surf along waterfronts of dilapidated wooden buildings.
"If the rain continues, we'll be flooded," U.N. consultant Jean Gardy said from the southeastern town of Marigot.
Patrice Tallyrand, 43, fled with his family to a friend's home after Gustav knocked down four trees in their backyard in the southern town of Kabik. "We had to leave the house before it got worse," he said.
Hundreds of people in coastal Les Cayes ignored government warnings to seek shelter, instead throwing rocks to protest the high cost of living in the Western Hemisphere's poorest country.
Oil prices shot up $5 a barrel Tuesday after the National Hurricane Center predicted Gustav could enter the gulf as a major hurricane this weekend. Prices of futures in natural gas, heating oil and gasoline also shot up.
U.S. gasoline prices could rise by 10 cents a gallon ahead of Labor Day weekend if Gustav continues on this path, according to James Cordier, president of Tampa, Florida-based trading firms Liberty Trading Group and OptionSellers.com.
"Most indications are that Gustav will be an extremely dangerous hurricane in the northwestern Caribbean Sea in a few days," the Miami-based National Hurricane Center said.
Forecasts often shift significantly as a storm develops, but projections suggested Gustav could slice along the south coast of Cuba and grow into a perilous Category 3 hurricane with 120 mph winds before entering the central gulf on Sunday.
That could force shutdowns on the offshore rigs that account for a quarter of U.S. crude production and much of its natural gas. Royal Dutch Shell PLC said it could begin evacuating workers as soon as Wednesday.
Projecting even further out, Accuweather.com said Gustav could grow into a Category 5 storm if it passes through the Yucatan Channel and enters the Gulf's warmer-than-usual waters. Hurricane Katrina struck three years ago this weekend as a Category 5 after shuttering most of the gulf's oil and natural gas production.
The U.S. military base at Guantanamo Bay, Cuba, had been expecting a direct hit, but later forecasts suggested the fiercest winds and rain will pass offshore. Base spokesman Bruce Lloyd said they were preparing for emergencies in any case.
In Haiti, the brunt of the storm appeared initially to have spared the capital, where businesses closed early and workers rushed home holding umbrellas, bags and boxes over their heads against the rain.
"I'm not too happy about it because I needed to get paid today," Darlene Pierre, 22, grumbled as she left a textile factory.
At Port-au-Prince's airport, stranded travelers mobbed the American Airlines counter, desperate to rebook tickets after the airline canceled all flights.
"I knew it was coming, but I was hoping to be out before it came," said Jody Stoltzfus, a 27-year-old missionary who had planned a visit home to Lancaster, Pennsylvania.
Haiti is particularly vulnerable to storms because so much of its land has been stripped of vegetation. Flooding killed more than 100 people in Haiti and scores in the neighboring Dominican Republic last year. In 2004, Tropical Storm Jeanne killed some 3,000 people in the Haitian city of Gonaives alone.
Tropical Storm Fay killed 23 people in Haiti and the Dominican Republic this month. Nearly all drowned in flooded rivers.
In Jamaica, officials alerted shelters to prepare for possible evacuations Wednesday, and Carnival Cruise Lines diverted one of its ships from Montego Bay, Jamaica, to a Mexican port, company spokesman Vance Gulliksen said. Other cruise lines were closely tracking Gustav's path.
Fay's remnants delivered heavy rain and winds from Georgia to Louisiana, and Floridians were still mopping up floodwaters from the storm, which made a historic four landfalls in Florida, dumping more than 30 inches (76 centimeters) of rain.
In Mexico, Tropical Depression Julio dissipated into a low pressure system, dumping rain over parts of the southwestern United States.