Hurricane Dean pounded the eastern Caribbean islands of St. Lucia and Martinique Friday, killing at least three people, and gaining strength as it moved westward towards Jamaica and Mexico's Yucatan Peninsula.

Hurricane Dean as seen from the international space station on Saturday.
(NASA TV/Associated Press)

The U.S. National Hurricane Center in Miami upgraded Dean to a Category 4 hurricane early Friday evening, with sustained winds of 217 km/h, and forecast it would become a Category 5 storm with winds of 250 km/h by Monday.

As the hurricane passed between Martinique and St. Lucia Friday, it caused flooding, downed trees, ripped off roofs and washed boulders from the sea into the middle of downtown streets.

On tiny St. Lucia, fierce winds tore corrugated metal roofs from
dozens of houses and a hospital's pediatric ward, whose patients
had been evacuated hours earlier. Police said a 62-year-old man
drowned when he tried to retrieve a cow from a rain-swollen river.

On the island of Martinique, a 90-year-old man died of a heart attack during the storm, French authorities said.

The government on Dominica, north of Martinique, reported that a woman and her 7-year-old son died in their sleep, after their hillside home was crushed by a landslide. Dominica suffered minor flooding, a few downed fences and battered crops, but in large escaped serious damage.

St. Lucia and Martinique
(CBC)

Hurricane warnings were posted for the south coast of Haiti and the Dominican Republic, which share an island to the northwest of St. Lucia and Martinique. Tropical storm warnings were posted for numerous other Caribbean islands, including the U.S. Virgin Islands, the British Virgin Islands, Montserrat, St. Kitts and Barbuda.

"Dean could become a very dangerous hurricane when it reaches the western Caribbean, where the ocean heat content is the highest," the U.S. hurricane centre said Friday.

Dean is forecast to brush the southern coast of Haiti late Saturday, then hit Jamaica on Sunday. The storm could reach the Yucatan by early Tuesday morning, forecasters said.

In Texas, Gov. Rick Perry warned residents to brace for wild weather after forecasters said Dean could threaten the U.S. by Wednesday.

Texas was hit Thursday by tropical storm Erin. At least four people died in the state as the storm dumped up to 25 centimetres of rain in some areas.

"[Dean is] so far out, but it's not too early to start preparing," said Katherine Cesinger, a spokeswoman for Perry. "We have more notice than with Erin. We're glad for that, especially since [Dean] is projected to bring some strength."

With files from the Associated Press