Jamaicans headed inland and tourists fled the country as a large and powerful Hurricane Dean appeared poised to make a direct hit on the island after a deadly and destructive march across the eastern Caribbean. Jamaica converted schools, churches and the indoor national sports arena into shelters and authorities urged people to take cover from a storm that could rake the country with winds of 150 and dump up to 20 inches of rain. "It's going to be very, very serious," said Lawrence Samuel as he shopped for emergency groceries while his wife and son went to the hardware store for plywood and other supplies. The storm, the first hurricane of the Atlantic season, rolled through the Caribbean to the south of Hispaniola, the island shared by Haiti and the Dominican Republic - where heavy rain and surging seas caused flooding Saturday in coastal areas. In Gonave, an island with no electricity west of the Haitian capital of Port-au-Prince, thousands of people huddled in the darkness in churches and schools and other inland shelters as the storm brought heavy rain and fierce winds, said Samuel Menager, an employee of the international aid group World Vision who helped evacuated people from the coast. Jamaican Prime Minister Portia Simpson Miller said late Saturday the country was confronting a national emergency and urged people in flood-prone areas to head for shelter. "Do not wait for the last minute to make the decision to move from where you are," Simpson Miller said. "Decide now and begin to make arrangements to leave now." Thousands of alarmed tourists were not waiting. They jammed Caribbean airports for flights out of Hurricane Dean's path as the fierce storm that has claimed at least six lives began sweeping past the Dominican Republic and Haiti. The storm's wrath could be felt Saturday in Santo Domingo, the capital of the Dominican Republic, where a boy was pulled into the ocean and drowned while watching waves strike an oceanfront boulevard, the Dominican emergency operations center reported. Rough surf churned by Dean destroyed five houses and damaged 15 others along the Dominican coast, emergency officials said. In Jamaica and the Cayman Islands, which was also in the path of the Category 4 storm, fear gripped many islanders and tourists alike. People jammed supermarkets and hardware stores in Kingston to stock up on canned food, bottled water, flashlights, batteries, lamps and plywood. In malls in the Jamaican capital, storeowners hammered plywood over windows. Elaine Russell recalled Hurricane Ivan's destruction in 2004. "I can't take it," she said. "The storm is bad enough but it's what happens afterwards - there's no light, no water." Farther west, the low-lying Cayman Islands were expected to take a direct hit on Monday. Tourists there jammed Owens International Airport in snaking lines that stretched outside onto a lawn. A police officer with a bullhorn kept order. Cayman Airways added 15 flights to Florida from the wealthy British territory, and they were quickly sold out. The government ordered a mandatory evacuation by noon Sunday of Little Cayman, which is the smallest of the territory's three islands and has a population of about 150. Authorities in the eastern Caribbean were assessing the damage after Dean hit on Friday as a Category 2 storm with winds of near 100 mph. In the island of Martinique, an overseas department of France, authorities on Saturday confirmed two deaths, including a woman who apparently fell and drowned in her home. Officials there estimated that â‚¬150 million to â‚¬200 million (US$200 million to US$270 million) is needed to repair infrastructure. Agriculture Minister Louis Daniel Berthome said all banana crops were destroyed. Dean was on course to clip Mexico's Yucatan Peninsula and enter the Gulf of Mexico by Tuesday, according to the National Hurricane Center in Miami. Forecasters said it was too soon to say whether it would strike the United States. Playing it safe, NASA shortened the last space walk for astronauts aboard the shuttle Endeavour and ordered the spacecraft to return to Earth on Tuesday - a day early - fearing the storm might threaten the Houston home of Mission Control. Rainfall could eventually total six inches in Haiti, where officials issued an alert for the coast and mountain communities made vulnerable to mudslides by deforestation. In 2004, Tropical Storm Jeanne triggered massive floods that killed 1,900 people and left 900 others missing. In St. Lucia on Friday, strong winds tore corrugated metal roofs from dozens of homes and the pediatric ward of a hospital, whose patients had been evacuated hours earlier. Police spokeswoman Tamara Charles said a 62-year-old man drowned when he tried to retrieve a cow from a rain-swollen river. In Dominica, a woman and her 7-year-old son were killed when a rain-soaked hillside gave way and crushed the home where they were sleeping, said Cecil Shillingford, the national disaster coordinator. Dominica's government reported at least 150 homes were damaged. At 11 p.m. EDT, Dean was centered about 360 miles east-southeast of Kingston, Jamaica, and about 170 miles south-southeast of Port-Au-Prince, Haiti. The storm was moving west at 17 mph and had maximum sustained winds near 145 mph. The Cuban government issued a tropical storm warning and said it was evacuating 50,000 people from three central and eastern provinces.