Super Typhoon Mawar has barrelled into Guam, hammering the US territory with hurricane-strength winds of up to 150mph and plunging residents into darkness.

The typhoon made landfall as a powerful Category 4 storm at around 9pm local time on Wednesday night, bringing with it heavy rains and a dangerous storm surge, the National Weather Service said.

Many homes and businesses were left completely without power and water as residents hunkered down inside houses and shelters.

The typhoon marks the strongest storm to hit the US territory in decades.

Video by cyclone interceptor James Reynolds shows lightning and havy gusts of wind as Typhoon Mawar passes close to Guam’s northern edge.

The heavy wind and rains have been lashing the US island territory all day, uprooting trees and blowing roofs as residents hunkered down in shelters.

Mawar was projected to pass 11 kilometres northeast of Andersen Air Force Base, close to the village of Yigo on the northern edge of Guam, between 6 and 8 pm.

As Guam residents hunker down and prepare for the arrival of Typhoon Mawar, another country – the Philippines – may soon have to bear the impact of the cyclone.

The typhoon is expected to reach the Philippines Area of Responsibility (PAR) on Friday evening or Saturday morning, according to Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA).

It would be given the local name Betty once inside PAR.The agency recorded Mawar 2,305 kilometres east of the Visayas island of the Philippines, moving north northwest at 10 kilometres per hour this morning.

While the chances of landfall in the Philippines appear slim, according to PAGASA, Rappler reported the agency saying that Mawar’s rainbands could still have some impact on Cagayan Valley in the north of Manila.

Video footage captured from International Space Station, posted by Space Portal, shows Typhoon Mawar inching close to Guam in the afternoon.

Another footage shared by Cooperative Institute for Research in the Atmosphere (CIRA) shows the heavy intensity of the typhoon.

Typhoon Mawar is yet to make landfall in Guam as of mid-afternoon. It was forecast to hit as a “super typhoon” of category 5, the worst the island had seen in decades.

However, the cyclone had weakened from category 5 strength to category 4, with maximum sustained winds were at about 225 kph.

Brandon Bukunt, a National Weather Service meteorologist in Guam told the New York Times its southern eyewall was still offshore, but had the potential to bring even stronger winds to the island, along with torrential rains.

Residents are worrying that the slow movement of Typhoon Mawar, as forecast by weather services, means more rain will end up lashing the island.

Joshua Paulino, a client manager at Xerox Guam, who is sheltering at home in the central village of Chalan Pago with his wife, two sons and mother, told the Associated Press he has closed the shutters and secured outdoor objects.

He expressed concern that the storm could dump rain on the island for a long time, since it was forecast to pass by gradually.

“This storm is moving very slowly so that is making me really uneasy,” Mr Paulino told AP by text message.

Guam’s weather service has warned of “considerable damage” from a “triple threat” of winds as Typhoon Mawar inches closer.

It said the typhoon is prompting torrential rains, apart from posing a threat of a life-threatening storm surge of 4 to 6 feet with dangerous surf of 20 to 30 feet.

If Guam doesn’t take a direct hit, it will be very close, said Patrick Doll, the lead weather service meteorologist in Guam.

Mawar is a Malaysian word that means “rose,” he noted.

The storm was moving at 10 kph but had an eye 27 kilometres wide, meaning people at the typhoon’s centre could see calm conditions for over three hours and conclude, far too soon, that the worst is over, Mr Doll said.

As the eye leaves, the winds could rise to 241 kph in minutes, so people should remain sheltered until the government gives the all-clear

.“Folks may say, ‘Hey it’s over, we could go outside and start cleaning up,”’ Mr Doll said. “That is totally wrong.

Photos and videos posted by residents and meteorologists show heavy gusts of wind in Guam as Typhoon Mawar inches close.

“Wind starting to pick up significantly, strong gusts thrashing the palm trees in Tumon Bay,” wrote James Reynolds, a tropical cyclone interceptor, sharing videos of palm trees amid winds.

“It’s going to be really, really rough,” he said in another video with heavy winds.

“The wind is so bad on Guam right now that it’s difficult to even hold the camera!” wrote a resident.

Other residents have also shared similar videos with audible turbulence.

Joe Biden today approved an emergency declaration as Typhoon Mawar grew to a Category 4 storm.

The US president sent back military ships and asked people with wood and tin homes to seek shelter elsewhere.

Federal assistance will be needed to save lives and property and “mitigate the effects of this imminent catastrophe,” Guam’s governor Lou Leon Guerrero said in a letter to the president requesting a “pre-landfall emergency” for the island.

Guam is a crucial hub for US forces in the Pacific, and the department of defence controls about a third of the island.