Guam residents were urged to stay home until the island is declared safe for travel, as the strongest storm in decades brought hurricane-force winds and heavy rain to the US territory.

The eye of Typhoon Mawar passed just north of Guam, but the eyewall – the strongest part of the storm – pelted the US territory with powerful winds and heavy rain.

Guam Gov. Lou Leon Guerrero urged residents to stay at home until conditions are declared safe for travel in a Facebook address Wednesday evening.

“Stay calm, stay informed and stay safe. We will get through this storm as we have in many, many other storms,” she said.

The governor said the strongest winds from the storm were currently being felt throughout the island, particularly in the north. These conditions will likely persist until the winds begin to decrease from around 8 or 9 a.m. Thursday, she said.

The Guam International Airport recorded sustained winds of 71 mph with a gust of 105 mph Wednesday evening.

The northern third of Guam, including the village of Yigo, is being battered by the strongest winds and heaviest rainfall as the storm moves northwest.

“Mawar is now moving away from Guam,” the National Weather Service in Guam said. The center of the storm was located about 55 miles north-northeast of Guam and was moving northwest at a sluggish 8 mph, the latest tropical cyclone advisory said.

At about 1 a.m. Thursday (11 a.m. Wednesday ET) the storm’s maximum sustained winds were 140 mph with gusts up to 165 mph, the equivalent of a Category 4 Atlantic hurricane, according to the Joint Typhoon Warning Center.

“Treat these imminent extreme winds as if a tornado was approaching and move immediately to an interior room or shelter NOW!,” the weather service in Guam warned Wednesday evening.

Even though the center of the storm’s eye passed just north of Guam, most of the island has lost power.

Nearly all of Guam Power Authority’s circuits have been impacted by the storm and only about 1,000 of its 52,000 customers still had electricity, the authority said in a statement on Facebook at around 6 p.m.

Guam Memorial Hospital is currently operating on power from a standby generator, it added. “We are working hard to maintain the last remaining customers through the storm,” the power authority said. “Our GPA team is prepared to immediately begin restoration as soon as winds decrease to safe levels,” it said.

The weather service issued a typhoon warning for the island for Wednesday, and flash flood and coastal flood warnings until Thursday morning.

In anticipation of high storm surge and potentially catastrophic coastal flooding, Guam Gov. Lou Leon Guerrero issued an executive order Tuesday mandating the evacuation of low-lying coastal areas.

“When sea levels rise, residents will have merely minutes to evacuate and respond. Thus, we must prepare now and anticipate the worst,” the governor’s office said in a release.

President Joe Biden approved an emergency declaration for the island on Tuesday, and FEMA announced it has more than 50 emergency relief personnel and dozens of other federal partners ready to provide emergency assistance on the ground.

‘Life-threatening’ floods from rain and storm surge possible

Mawar threatens “torrential rains that may result in landslides and flash flooding, catastrophic wind, and life-threatening storm surge,” the weather service said Wednesday morning.

Mawar’s slow forward pace of about 8 mph could exacerbate the impacts of wind and bring greater amounts of rainfall to the island than a faster-moving storm.

The storm could bring between 15 to 20 inches of rain with even higher local amounts possible, the weather service said. The downpour will likely trigger landslides, overflow rivers and streams and bring flooding to areas that don’t normally see such events.

While the storm surge is expected to be lower than initially feared, as the center of the storm passed just north and kept the worst of the surge north of the island, ocean levels 4 to 6 feet above normal high tides are still possible, the weather service warned.

Maximum observed wave heights over the ocean were a towering 40 feet high.

Storm surge deaths are historically the leading cause of hurricane-related fatalities within the United States, according to the weather service.

Officials have warned the storm will bring devastating impacts to the island’s residents, infrastructure and landscape.

Extensive roof and structure damage is possible due to pummeling winds, especially for buildings that are not reinforced with concrete.

“Electricity and water may be unavailable for days and perhaps weeks after the storm passes” and “most trees will be snapped or uprooted,” the local weather service warned.

Between 50-70% of Guam’s vegetation could experience defoliation – the unnatural removal of much of a plant’s leaves and foliage, the weather service said.

Human-caused climate change is contributing to an upward trend intense storms like Typhoon Mawar. Not only are these systems generating more rainfall and larger storm surge – they are also more likely to be stronger and are intensifying faster, CNN has reported.

Mawar rapidly intensified from Monday into Tuesday, with top wind speeds increasing by 50 mph in just 18 hours. Scientists have warned that the rapid intensification of tropical cyclones – like typhoons and hurricanes – is more likely as ocean temperatures climb and lay the groundwork for cyclones to explode at breakneck pace into deadly storms.

Strongest storm in decades

The storm is “one that will be remembered for decades,” said Landon Aydlett, the warning coordination meteorologist for the weather service in Guam.

Mawar is the strongest storm to impact Guam – home to about 150,000 people, as well as several US military installations – in decades. Super Typhoon Pongsona hit Guam in 2002 with sustained winds of 144 miles per hour and gusts to 173 mph, according to the weather service.

Super Typhoon Karen, widely regarded as the worst storm to ever hit the island, struck in 1962 with sustained winds of 172 mph.

Though Guam sits in the West Pacific Ocean – an area prone to the world’s strongest tropical cyclones – it is extremely rare for the island to be struck directly by a storm of this strength. Hitting the small island amid the expansive Pacific Ocean is like threading a tiny needle. Only eight storms of this strength have passed directly over it in the last 75 years.