A tropical cyclone killed at least six people in Vanuatu, UNICEF said Saturday, confirming first casualties from one of the most powerful storms ever to make landfall.

 

Hardly a tree stood straight after Tropical Cyclone Pam bellowed across the Pacific island nation.

 

Aid workers fear many more fatalities. The confirmed deaths came only from the capital, Port Vila.

 

Only a little information has so far trickled out from areas outside the capital, but Sune Gudnitz, regional head for U.N. aid agency OCHA told CNN from Fiji, about 600 miles away, that he fears the worst.

 

"Unfortunately, the more that comes out, the worse it looks," said Gudnitz. "I should say it's really a case of the worst-case scenario for the country and for the people."

 

His agency has had word of much destruction on Efate, the island that houses the capital, where Pam's eye roared through, and from the southern island of Tanna, he said.

 

But many areas remain out of contact. And widespread wiped-out communications could indicate desolation.

 

'Unbelievable destruction'

 

Pam had churned through the South Pacific with the might of a Category 5 hurricane before notching down to Category 4 after landfall at 11:23 p.m. Friday local time. CNN's Weather Center said 155 mph (250 kmh) winds blasted the island nation.

 

There were gusts up to 200 mph (325 kmh). And the cyclone's damage has stunned relief workers.

 

"Unbelievable destruction," the Australian Red Cross called it, particularly in terms of human suffering. "Humanitarian needs will be enormous. Many people have lost their homes. Shelter, food and water (are) urgent priorities," the aid agency said in a tweet.

 

The main objective now is to get disaster response teams into Vanuatu and kick-start the humanitarian operation, said Gudnitz.

 

But the airport in Port Vila has been damaged and it's not clear when it will be able to reopen to allow relief flights to land. The U.N. aid agency hopes to get its first team on the ground with vital aid on Sunday, Gudnitz said.

 

Vanuatu's remote location won't help the international response. Port Vila is more than 1,100 miles northeast of Brisbane on Australia's east coast, and some 1,375 miles north of Auckland, the closest city in New Zealand.

 

Until international teams can get in, it will be up to humanitarian agency staffers on the ground and the local communities themselves to do what they can among the wreckage.

 

Trees piled high

 

Alice Clements spent the night cowering under the bathroom sink.

 

"But all what I could think about during that time is the people who might be literally clinging to coconut trees for their lives, and trying to hold on in those horrific winds," the UNICEF spokeswoman said.

 

There's no power in the whole of Vanuatu, Clements said, making it impossible for people to recharge their cell phones to call in. The water supply is also cut off, adding to people's difficulties.

 

After Pam passed, World Vision emergency specialist Chloe Morrison took a drive around part of the island that is home to the capital.

 

"Port Vila looks like an absolute bomb has hit it," she said. Images showed trees toppled to the ground, along with corrugated metal roofing strewn around like silver wrappers.

 

Trees blocked the path of Morrison's vehicle. "They've fallen across in piles so high in some places you can barely see over the top," she said.

 

Strongest since Haiyan

 

Pam is the strongest storm to make landfall in the Pacific typhoon region since Haiyan raked over the Philippines in 2013, obliterating parts of Leyte.

 

It shattered homes and trees into match sticks, and killed more than 6,000 people.

 

Vanuatu's capital may have been luckier than Leyte.

 

City on lockdown

 

Many roads are obstructed in Port Vila, and police had put the city on temporary lockdown, Gudnitz said. But there are some solid structures there to protect people. And in the first images out of the city, many buildings looked intact.

 

The capital may be a fortunate exception.

 

The nation, which lies east of Australia, is an archipelago comprising 83 small islands, about 65 of them inhabited and many remote and lacking infrastructure. People away from the capital live much like their ancestors did generations ago.

 

Homes are built of weaker materials, including straw and corrugated steel, and may have had little stamina against Pam's raging winds.

 

Huts around Port Vila were destroyed, Morrison said.

 

"This is often a tropical paradise island and a lot of these houses are what you would expect on an island. They are thatched roofs and thatched walls, and just not able to withstand a Category 5.

 

"We've seen villages literally blown away."

 

Pam "left no island untouched," she added. "And the devastation that will be on those smaller, remote islands -- I can't even imagine it."

 

"Once we start looking further afield from Port Vila, we are going to see more destruction because the houses there would be in a much different condition from what we have in Port Vila," Gudnitz said.

 

"It's a disaster, there's no other way to describe it, really."

 

Hunkered down, terrified

 

Even in a concrete house in Port Vila, emergency worker Morrison was terrified of the whirring force. She huddled in a back room with seven other people.

 

"Seven hours hunkered down and it's still not safe to go outside," she said early Saturday. "The winds are still really howling." It sounded like there was an angry ocean at their door.

 

As a piece of tin twisted off the roof and landed by a window, Morrison felt lucky to be shielded by solid walls.

 

One positive amid the devastation is that the people of Vanuatu have known that Pam was coming for more than a week, giving time for people to evacuate to shelters, though not every island even has a concrete structure, Morrison said.

 

The biggest priority now for many will be access to clean water, she said. In some outlying communities this was difficult even before Pam hit.

 

There is also the issue of food. Many people on Vanuatu's islands are subsistence farmers and the cyclone may have destroyed most or all of the crops they rely on to survive.

 

World Vision's staff hopes preparations will have paid off. They had positioned clean water, food, blankets, tarpaulins, and shelter, hygiene and kitchen kits in key places before the cyclone arrived.

 

Next cyclone brewing

 

Pam has now moved southeastward beyond the southern islands of Vanuatu and winds are expected slowly to ease, the Vanuatu Meteorological Department said Saturday evening.

 

In the meantime, very rough seas with heavy swells will continue to affect the waters surrounding Vanuatu, with heavy rainfall and flooding expected throughout the central and southern islands, it said.

 

The storm wasn't expected to make any additional landfalls before dissipating. It will continue to weaken as it crosses cooler waters and encounters higher wind shear.

 

But over Queensland, Australia, a new cyclone, Nathan, is brewing. It is expected to reach Vanuatu this week.

(CNN)