Storm sparking alarm and alerts; authorities brace for 'catastrophe'

SAN JUAN, Puerto Rico - Hurricane Irma, a powerful Category 4 storm, plowed 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 parts of the Leeward Islands, the British and US Virgin Islands and Puerto Rico, in preparation for a storm that was intensifying with 240 km/h winds, the US National Hurricane Center said.

"Dangerous Hurricane Irma heading for the Leeward Islands," the hurricane center said. "Preparations should be rushed to completion as tropical storm-force winds are expected to arrive in the hurricane warning area by late Tuesday."

A Category 4 hurricane on the five-step Saffir-Simpson scale means sustained winds of 210-250 km/h with "catastrophic" outcomes. They range from uprooted trees and downed power lines to water and electricity outages and enough damage to leave property uninhabitable, according to the Miami-based hurricane center.

In preparation for the storm, the government of economically struggling Puerto Rico has declared a state of emergency and activated the National Guard. The US territory, home to about 3.4 million people, has 456 emergency shelters prepared to house up to 62,100 people. Puerto Rico also froze prices on basic necessities, including food and water, medicines, power generators and batteries, to help residents prepare.

Telemundo TV station WIPR in Puerto Rico showed long lines of shoppers stocking up on bottled water, flashlights, batteries, generators, food and other items.

Irma also threatens the US East Coast and Florida, which has declared a state of emergency. The hurricane center expects Irma to reach southern Florida on Saturday.

Florida Governor Rick Scott said on Twitter late on Monday he had spoken to President Donald Trump, who he said "offered the full resources of the federal government as Floridians prepare for Hurricane Irma".

The NHC cautioned that it was too early to forecast the storm's exact path or what effects it might have on the continental United States, but warned of likely effects to hit some areas by later this week.

"There is an increasing chance of seeing some impacts from Irma in the Florida Peninsula and the Florida Keys later this week and this weekend. In addition, rough surf and dangerous marine conditions will begin to affect the southeastern US coast by later this week," the center said.

Irma will be the second powerful hurricane to thrash the US and its territories in as many weeks.

Residents of Texas and Louisiana are still reeling from the catastrophic effects of Hurricane Harvey, which struck Texas as a Category 4 hurricane on Aug 25 and dumped heavy rain, destroying thousands of homes and businesses.

Reuters - Ap