Los Angeles (AFP) - Typhoon Mawar made a slow and brutal pass over the US territory of Guam on Wednesday, knocking out power as ferocious winds smashed windows and storm surges flooded buildings in the worst storm to hit the Pacific military outpost in decades.

People on the remote speck of America hunkered down as the eye of the storm passed just north of the island with winds gusting at up to 140 miles (225 kilometers) per hour.

Electricity to most of the island of some 170,000 people was knocked out, the Guam Power Authority said, and it was too risky for repairs crews to venture out, leaving residents facing a long dark night of noisy and dangerous weather.

“It’s going to be scary. There’s no electricity unless you have a generator (or) partial generator. Reassure your children,” Brandon Aydlett, a National Weather Service operations officer, told a briefing, according to The Guam Daily Post.

Waves of up to 30 feet (nine meters) were seen southeast of the island, he said.

The newspaper said the storm was passing over the northern tip of the island “excruciatingly slowly.”

At one of the island’s many hotels, the 30-floor Dusit Thani Guam Resort housing about 300 guests, desk clerk Casey Hattori said the lobby was flooded with a foot of water even with the front door barricaded with boards and bags of concrete. Outside, trees snapped in howling wind.

“I can hear the walls shaking. The wind is super strong. I can hear it whistling as it comes through the cracks of the doors,” Hattori told AFP.

Fearful tourists were evacuated from flooded rooms to a sixth floor ballroom, she said.

Governor Lou Leon Guerrero said the eye of the typhoon passed over the Rota Channel, a body of water between the islands of Guam and Rota.

Local authorities earlier issued evacuation orders and opened temporary shelters while, in faraway Washington, President Joe Biden declared a state of emergency paving the way for federal aid.

“I am worried for the safety of our people. This is the first storm of this magnitude for 20 years,” Guerrero said.

- Major US military base -

The NWS warned of the triple threats of torrential rain, catastrophic winds and a life-threatening storm surge.

“Surge may reach to between 20 and 25 feet above normal high tide for the most vulnerable storm-surge-prone areas near the eye wall,” it said.

Forecasts predicted Guam will receive rainfall of 10 to 15 inches, with some areas seeing 20 inches or more.

People were told to stay inside and away from windows, and not venture outside during temporary lulls as flying debris could cause serious injury.

About 21,700 US military personnel and their families are based at or near several facilities on Guam, which routinely hosts nuclear attack submarines and long-range bombers.

The territory is also home to key electronic listening posts, and the US bases have some of the Pacific region’s most significant ammunition and fuel storage facilities.

About 60 flights scheduled to depart or arrive in Guam between Tuesday and Thursday were canceled, A.B. Won Pat International Airport said.

Conditions in Guam are expected to improve on Thursday, but the storm is expected to intensify over the next few days, possibly becoming a super typhoon over the Philippine Sea, the NWS said.