(CNN) The mayhem of Tropical Cyclone Pam, one of the most powerful storms ever to make landfall, is gone, but the misery it left behind in the islands of Vanuatu is just becoming apparent.

Aid workers in the capital of Port Vila described homes and shops flattened, swaths of trees plowed over and residents seeking shelter in schools and churches -- or with neighbors.

At least six people are dead, but communication with many of the 80-plus islands in the archipelago is impossible, so the fear is that toll will climb. The deaths reported by the National Disaster Management Office are just from Port Vila.

It is unclear how many thousands will be displaced by the massive storm that bore the might of a Category 5 hurricane when it pounded the islands for most of a 24-hour period.

"It's like a bomb has gone through," said journalist Michael McLennan, who lives in Port Vila. "It's really quite apocalyptic."

Most buildings were destroyed or damaged, he told CNN on Sunday morning. Many roads are blocked by fallen trees or power lines.

Hardly a tree stood straight after Pam bellowed across the South Pacific nation, where some 260,000 people live, many in flimsy homes built of thatch.

Cleanup efforts are underway, according to Colin Collet van Rooyen, Oxfam country director in Vanuatu.

It appears Bauerfield International Airport will reopen Sunday afternoon for emergency flights. An Australian C-130 took off for Port Vila with emergency personnel from the defense department. The Australian air force will send two cargo planes loaded with relief supplies, the government in Canberra announced.

The main objective now is to get disaster response teams into Vanuatu and kick-start the humanitarian operation, Sune Gudnitz, regional head for U.N. aid agency OCHA, told CNN from Fiji, about 600 miles away.

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

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Only a little information has so far trickled out from beyond the capital, but Gudnitz, said 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."

Vanuatu President Baldwin Lonsdale, who was at a U.N. conference on disaster reduction in Japan on Saturday, appealed for help for his shattered nation.

Photos: Tropical Cyclone Pam hits Vanuatu Photos: Tropical Cyclone Pam hits Vanuatu A woman sits on a fallen tree among what's left of her garden in Port Vila, Vanuatu, on Thursday, March 19, nearly a week after Cyclone Pam ripped through the island nation in the South Pacific. Vanuatu President Baldwin Lonsdale has called the storm a "monster," saying it has set back the development of his country, already one of the poorest in the region, by years. Hide Caption 1 of 34 Photos: Tropical Cyclone Pam hits Vanuatu A young boy plays on a destroyed banana plantation in Mele, Vanuatu, on March 19. Hide Caption 2 of 34 Photos: Tropical Cyclone Pam hits Vanuatu A nun surveys the damage near Port Vila on March 19. Hide Caption 3 of 34 Photos: Tropical Cyclone Pam hits Vanuatu People put clothes out to dry near Port Vila on March 19. Hide Caption 4 of 34 Photos: Tropical Cyclone Pam hits Vanuatu An aid worker treats an injured woman on Tanna Island on Wednesday, March 18. Hide Caption 5 of 34 Photos: Tropical Cyclone Pam hits Vanuatu A child walks through a damaged classroom on Tanna Island on March 19. Hide Caption 6 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Mercy Watskal holds her week-old granddaughter, Angelina, at the Enima Evacuation Center on Tanna Island on March 19. Hide Caption 7 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Young men take apart a damaged hut on March 19 on Tanna Island. Hide Caption 8 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Australian doctors help a young girl on the Vanuatu island of Tanna on Wednesday, March 18. Hide Caption 9 of 34 Photos: Tropical Cyclone Pam hits Vanuatu A man stands under the damaged rooftop of a school in Vanuatu's capital, Port Vila, on March 18. Hide Caption 10 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Books recovered from a school are left out to dry in Port Vila on March 18. Hide Caption 11 of 34 Photos: Tropical Cyclone Pam hits Vanuatu A ship sits beached along the shore of Tanna on March 18. Hide Caption 12 of 34 Photos: Tropical Cyclone Pam hits Vanuatu An Australian army relief aircraft arrives with supplies at the airport in Tanna on March 18. Hide Caption 13 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Residents clean up debris in Port Vila on Tuesday, March 17. Hide Caption 14 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Children play on March 17 in water among fallen trees near Port Vila. Hide Caption 15 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Aid is on board a Royal Australian Air Force C-17 Globemaster transport aircraft headed to Port Vila on Monday, March 16. Hide Caption 16 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Debris from the cyclone is scattered in an area near Port Vila on March 16. Hide Caption 17 of 34 Photos: Tropical Cyclone Pam hits Vanuatu A boy kicks a ball through the ruins of his family home as his father picks through debris on March 16. Hide Caption 18 of 34 Photos: Tropical Cyclone Pam hits Vanuatu A bridge and road that suffered dramatic damage from Cyclone Pam are seen outside Port Vila, the capital of Vanuatu, on Sunday, March 15. Hide Caption 19 of 34 Photos: Tropical Cyclone Pam hits Vanuatu A resident stands in her badly damaged home outside Port Vila on March 15. Hide Caption 20 of 34 Photos: Tropical Cyclone Pam hits Vanuatu An aerial photo taken by CARE Australia on March 15 shows the widespread damage caused by the cyclone in Vanuatu. Hide Caption 21 of 34 Photos: Tropical Cyclone Pam hits Vanuatu A resident clears mud and other debris outside homes near Port Vila on March 15. Hide Caption 22 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Residents work amid the debris left by the cyclone outside Port Vila on March 15. Hide Caption 23 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Locals walk past debris in Port Vila on March 15. Hide Caption 24 of 34 Photos: Tropical Cyclone Pam hits Vanuatu People walk past debris scattered on a street in Port Vila, Vanuatu, on Saturday, March 14. Hide Caption 25 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Damaged boats are seen on Saturday, March 14, in Port Vila, Vanuatu's capital. Hide Caption 26 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Surf pounds the shore as people walk among debris scattered by Cyclone Pam in Port Vila, Vanuatu, March 14. Hide Caption 27 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Residents look through storm damage in Port Villa on March 14. Hide Caption 28 of 34 Photos: Tropical Cyclone Pam hits Vanuatu People move away from the beach March 13 on the island of Kiribati. Hide Caption 29 of 34 Photos: Tropical Cyclone Pam hits Vanuatu A person walks past flooding near Port Vila on March 13. Hide Caption 30 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Strong winds blow trees as Pam hits Vanuatu on March 13. Hide Caption 31 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Shops are boarded up in Port Vila on Thursday, March 12. Hide Caption 32 of 34 Photos: Tropical Cyclone Pam hits Vanuatu Preparations are made in Port Vila ahead of the storm on March 12. Hide Caption 33 of 34 Photos: Tropical Cyclone Pam hits Vanuatu People in Port Vila buy supplies ahead of the storm on March 12. Hide Caption 34 of 34

"I am speaking with you today with a heart that is so heavy. I do not really know what impact Cyclone Pam had left on Vanuatu, as there are no confirmed reports as yet," he said.

"I stand to appeal on the behalf of the government and people of Vanuatu to the global community to give a lending hand in responding this very current calamities that have struck us."

'Unbelievable' destruction

Pam was the equivalent 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 kph) winds blasted the island nation, with gusts up to 200 mph (325 kph).

By overnight Saturday, the damage was done. CNN meteorologist Ivan Cabrera noted that, by then, Pam had passed all the nation's islands and was moving over open water.

As it moved over cooler ocean waters away from Vanuatu, the storm further weakened Sunday. It had sustained winds of 132 mph (213 kph), said the Joint Typhoon Warning Center in Pearl Harbor, Hawaii.

The damage it left behind is "unbelievable," according to the Australian Red Cross.

"Humanitarian needs will be enormous," the aid agency tweeted. "Many people have lost their homes. Shelter, food and water (are) urgent priorities. "A UNICEF Australia post, meanwhile, spoke of "countless homes torn apart, communities in ruin."

"It's like a bomb has gone off in the centre of the town," our colleague says. Countless homes torn apart, communities in ruins. #CyclonePam — UNICEF Australia (@unicefaustralia) March 14, 2015

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.

Many people will be spending another night in emergency shelters.

Trees piled high

At least they won't have to face the horrors of the height of the storm.

At that point, Alice Clements was cowering under a 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.

.@UNICEFPacific Alice Clements shared this extremely emotional update from the heart of #CyclonePam last night: http://t.co/mvF0GhGNNi — UNICEF New Zealand (@UNICEFNZ) March 14, 2015

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.

Another UNICEF staffer in Port Vila, Andrew Parker, told CNN that he'd been through many cyclones, but this one "just went on and on forever."

The winds and rain only started to subside about 1 or 2 p.m. on Saturday, he said, having raged since 5 p.m. on Friday. Port Vila alone ended up with about 9 inches (230 mm) of rain in a 36-hour period, which is 70% of its rainfall for the month.

Only one cell phone tower was still standing in the whole of the archipelago, in Port Vila, according to Parker.

Vanuatu has officially declared a state of emergency due to devastation caused by Pam, opening the door for other countries -- like Britain, which is already offering almost $3 million -- to help.

"Port Vila looks like an absolute bomb has hit it," World Vision emergency specialist Chloe Morrison said.

Trees blocked the path of Morrison's vehicle as she drove around the capital. "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 South Pacific's second strongest cyclone since record-keeping began in 1970. And it's the strongest of any type since Super Typhoon Haiyan smashed the Philippines in 2013, obliterating parts of Leyte.

Vanuatu, 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.

"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," Morrison said.

"We've seen villages literally blown away."

Villages 'literally blown away'

Pam "left no island untouched," Morrison 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."

The Adventist Development and Relief Agency, the humanitarian arm of the Seventh-day Adventist Church, said it was still waiting to hear from all its team in Vanuatu. Five have not been accounted for on Pentecost Island and five on Malakula Island, presumably unable to communicate because cellular networks are down, the organization said.

Field staff have reported that even families whose homes had survived two previous cyclones lost them during Pam.

"Families are trying to gather as much as they can," said Mark LeRoux, the organization's Vanuatu country director. "Even sturdy houses didn't make it -- walls and roofs came down."

Hunkered down, terrified

Even in a concrete house in Port Vila, emergency worker Morrison was terrified by 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.

Cyclone Pam's projected path

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 Vanuatu has 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. McLennan, the journalist who lives in Port Vila, said crops with roots fared much better through the storm than those that grow on trees.

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 isn't done yet, heading south-southeast at a 32 mph (52 kph) clip, the Meteorological Service of New Zealand reported at 7 a.m. Sunday.

It should start affecting New Zealand's North Island late Sunday, though the good news -- according to CNN's Cabrera -- is that it won't be the same "monster storm."

The weather service said, "Heavy rain and strong wind warnings and watches are in force for the northern and eastern parts of the North Island from this evening through to Tuesday. "

New Zealand's official weather agency forecasts up to 8 inches of rain and 100 mph wind gusts in parts of that island, though the overall impact won't be anywhere near as bad as in Vanuatu.

In the meantime, a new cyclone -- Nathan -- is brewing over Queensland, Australia. It is expected to reach Vanuatu this week.