Hurricane Dean has strengthened into an extremely dangerous Category four hurricane as it crossed the Caribbean Sea toward Mexico's Yucatan Peninsula and the Gulf of Mexico.
The Miami-based US National Hurricane Center said Dean's top sustained winds had surpassed 215 kph.
Category three to five 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 centre.
