Hurricane Irma, a powerful Category 4 storm, ploughed toward the Caribbean and the southern United States on Tuesday as islands in its path braced for possible life-threatening winds, storm surges and flooding.

Hurricane warnings and watches were in effect for territories that dot the West Indies, including parts of the Leeward Islands, the British and U.S. Virgin Islands and Puerto Rico, in preparation for a storm that was intensifying with 140 mph (220 kph) winds, the U.S. National Hurricane Center (NHC) said.

The National Weather Service said in an advisory on Monday: “Preparations should be rushed to completion as tropical storm-force winds are expected to arrive in the hurricane warning area by late Tuesday.”