Hurricane Dean strengthens to Category 4 Storm

MIAMI, Aug 18 (Reuters) Hurricane Dean strengthened into an extremely dangerous Category 4 hurricane on Friday as it crossed the Caribbean Sea toward Mexico's Yucatan Peninsula and the Gulf of Mexico beyond it, US forecasters said.

In an advisory at 8 pm local time yesterday the Miami-based National Hurricane Center said Dean's top sustained winds had surpassed 215 kph on the five-step Saffir-Simpson scale of hurricane intensity.

Category 3 to 5 hurricanes, such as Katrina, Rita and Wilma in the devastating 2005 Atlantic storm season, are potentially the most destructive storms and are collectively referred to as ''major'' or ''intense'' by the hurricane center.

Reuters SZ VP0612