Howling winds and lashing rains are battering Guam and the Northern Mariana Islands as super typhoon Bavi makes landfall.
Packing winds of nearly 290km/h (180mph) and gusts of 350km/h, the western eye of Bavi is moving over the Pacific islands, according to the US National Weather Service (NWS).
The NWS warned the "very dangerous" storm could cause "catastrophic" damage, with waves potentially nearly 11m (35ft) high.
The western Pacific region is particularly prone to tropical cyclones. While storms of this strength are unusual for the US islands, scientists say climate change is making powerful typhoons more common.
Residents in the region have been moving to emergency shelters and making last-minute preparations before the arrival of the super typhoon.
In the Northern Mariana Islands, Rota - the southernmost inhabited island, about 50km north-east of Guam - is taking a direct hit, according to the NWS.
The mayor's office has published an advisory urging residents to prepare for "destructive winds", adding that "conditions are expected to deteriorate rapidly, making it unsafe to be outdoors".
The NWS also warned that winds are not forecast to fall below typhoon force until early afternoon on Monday, and below tropical storm force until after midnight.
Guam, usually a sun-soaked tourist destination with a population of about 170,000, has opened five evacuation centres in its schools. These sites have a maximum capacity of around 1,700 and are primarily intended for vulnerable people.
The island's civil defence office said at 13:00 local time on Sunday that one of the evacuation sites had already reached maximum capacity and that people were being redirected to another site.
Bavi has been classified as a super typhoon by the Joint Typhoon Warning Center (JTWC), a part of the US military responsible for monitoring tropical storms in the western Pacific.
A super typhoon has winds in excess of 240km/h. The NWS considers super typhoons to have the equivalent destructive potential as a category four or five hurricane.
Pinky Cubacub, 55, told news agency AFP that she had been boarding up the windows of her eatery in Guam with $500 (£373) worth of plywood.
"I cannot afford to lose so many days. It hurts," she said. "Because I just started, whatever we're making right now is just for rent, utilities, and my people, and supplies. I don't even pay myself yet."
Japanese tourist Miku Sakurai, 25, told AFP that her return flight to Tokyo on Sunday had been cancelled.
"We will stay in the hotel when the storm comes. I am scared," she said.
Bavi will be the 11th category four or five tropical cyclone to hit US territory in the past decade - one more than the total recorded in the prior 57 years.
A strong El Niño event - a periodic warming of an area of surface water in the Pacific that contributes to weather patterns - is expected to push more tropical storms into these higher intensities.
Guam and the Northern Mariana Islands have already experienced one super typhoon this year - Sinlaku in April, which killed 17 people and caused about $1.5bn (£1.1bn) in damage.
Warmer sea surface temperatures drive more moisture into the atmosphere, supercharging storms.
Source:BBC
--Agencies
