Hurricane Irma Barrels Toward the U.S. Mainland

Updated at 5:00pm:

MIAMI (AP) – Hurricane Irma has strengthened into a Category 4 storm as it approaches the northeast Caribbean.

The storm’s center is 490 miles (790 kilometers) east of the Leeward Islands late Monday afternoon. It has maximum sustained winds of 130 mph (215 kph) and is moving west at 13 mph (20 kph).

Emergency officials are warning that Irma could dump up to 10 inches (25 centimeters) of rain, unleash landslides and dangerous flash floods and generate waves of up to 23 feet (7 meters) as the storm draws closer.

A hurricane warning has been issued for Antigua and Barbuda, Anguilla, Montserrat, St. Kitts and Nevis, St. Martin, Saba, St. Eustatius, St. Maarten and St. Barts. A hurricane watch is in effect for Puerto Rico, Vieques, Culebra, the British and U.S. Virgin islands and Guadeloupe.

Original:

(CNN) — The newest hurricane that could threaten North America intensified Monday morning, though its future path remains uncertain.

As of 11 a.m. ET on Monday, Hurricane Irma was about 560 miles east of the Leeward Islands, the National Hurricane Center said. It’s packing maximum sustained winds of 120 mph as it heads west-northwest at 14 mph.

“Swells generated by Irma will begin affecting the northern Leeward Islands today,” the NHC said Monday. “These swells are likely to cause life-threatening surf and rip current conditions.”

A string of Caribbean islands are now under hurricane warnings, including Antigua, Barbuda, Anguilla, Montserrat, St. Kitts, Nevis, Saba, St. Eustatius, St. Martin/Sint Maarten and St. Barts, the NHC said.

“A hurricane warning means that hurricane conditions are expected somewhere within the warning area,” the hurricane center said. “A warning is typically issued 36 hours before the anticipated first occurrence of tropical-storm-force winds, conditions that make outside preparations difficult or dangerous. Preparations to protect life and property should be rushed to completion.”

And Irma will only intensify in the coming days, CNN meteorologist Allison Chinchar said. “Right now, Hurricane Irma is a Category 3 storm,” she said. “But over the coming days, it’s going to get into that warmer water. That’s going to help the storm intensify.”

Puerto Ricans Warned

Irma is expected to remain a “dangerous major hurricane” through the week and could directly affect the British and US Virgin Islands, Puerto Rico, Hispaniola, Turks and Caicos, and the Bahamas, the agency said.

Puerto Rico Gov. Ricardo Rosselló warned the public on Sunday that the island could feel Irma’s wrath around noon Wednesday.

Puerto Rico’s disaster management agency (AEMEAD) is monitoring Irma and has opened an information hotline.

Florida Governor Says Be Prepared

It’s too soon to know the impact Irma could have on the continental United States, where no warnings or watches are currently in effect.

“Regardless, everyone in hurricane-prone areas should ensure that they have their hurricane plan in place, as we are now near the peak of the season,” the National Hurricane Center said.

Chinchar said Irma could impact not just the eastern coast of Florida, but also farther up the east coast.

“If there was a US landfall, we’re talking a week from today,” Chinchar said Monday.

Florida Gov. Rick Scott urged the state’s residents to ensure their disaster supply kits were ready.

“Florida knows how important it is to be prepared. Encourage your loved ones to have a plan ahead of any potential storm,” Scott tweeted Sunday. “Disaster preparedness should be a priority for every Florida family.”

Why Irma Could Be Especially Intense

Irma is a classic “Cape Verde hurricane,” meaning it formed in the far eastern Atlantic, near the Cape Verde Islands (now known as the Cabo Verde Islands), before tracking all the way across the Atlantic, CNN meteorologist Brandon Miller said.

And Cape Verde storms frequently become some of the largest and most intense hurricanes. Examples include Hurricane Hugo, Hurricane Floyd, and Hurricane Ivan.