Already packing devastating power and expected to intensify further, Hurricane Dean began battering the south coasts of Haiti and the Dominican Republic on Saturday with howling winds and heavy rains as it churned northwest through the Caribbean.

Haitian authorities issued an alert for coastal communities where thousands of people live in flimsy shacks. All flights from the capital, Port-au-Prince, were canceled on Saturday and small boats were prohibited from leaving shore, the country’s disaster management agency said.

Elsewhere, alarmed tourists jammed Caribbean airports for flights out of Hurricane Dean’s path. In Santo Domingo, the capital of the Dominican Republic, an 11-year-old boy was killed by flying debris while watching large waves strike an oceanfront boulevard, the Dominican emergency operations center reported.

Dean was forecast to thrash Jamaica with 160 mph winds, or Category 5 intensity, up to 20 inches of rain, storm surge and large battering waves, with the onslaught beginning Sunday morning. The system, with hurricane-force winds extending 70 miles from its core, was to be directly over the small island nation by Sunday afternoon.

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