Hurricane warnings were posted for the Cayman Islands, Jamaica, Haiti and eastern Cuba, including the U.S. Navy base at Guantanamo Bay, where some 520 terror suspects are detained. Forecasters also warned Dennis was on track for the Alabama-Florida coastline.
Dennis came right behind Tropical Storm Cindy, which made landfall late Tuesday in Louisiana and hindered oil production and refining. Traders said that uncertainty over both storms helped to push oil prices to new highs.
Packing sustained winds near 105 mph, the fourth storm of the Atlantic season — and its first hurricane — could dump up to 15 inches of rain over mountains in its path, including Jamaica's coffee-producing Blue Mountains, according to the U.S. National Hurricane Center in Miami.
At 8 a.m. EDT, Dennis was about 130 miles east-southeast of Kingston, Jamaica.
Last year three hurricanes — Frances, Ivan and Jeanne — tore through the Caribbean with a collective ferocity not seen in many years, causing hundreds of deaths and billions of dollars in damages.
Inside the detention center at Guantanamo Bay, the military prepared audio tapes in at least eight languages warning that a storm was coming and heavy steel shutters would be closed on some cell windows, said Col. Mike Bumgarner.
Military officials had no immediate plans to evacuate troops or detainees at Camp Delta, which is about 150 yards from the ocean but was built to withstand winds up to 90 mph, according to Navy Cmdr. Anne Reese, supervisor of camp maintenance and construction.
Power lines could be knocked down and roofs could be damaged on some older, wooden buildings, Reese said.
"It will be bad, but it's not going to be very destructive," she said.
Bumgarner said the military had a contingency plan to move the prisoners if conditions became serious.