Hawaiian officials are still determining what caused a deadly wildfire to sweep through Lahaina on Maui island in Hawaii with terrifying speed, killing at least 67 people and decimating the historic resort town with little warning to residents.

The death toll was expected to rise as search teams combed through the charred ruins of the town with the aid of cadaver dogs, after the fire torched 1000 buildings and left thousands of people homeless in what officials say is the worst natural disaster in the state’s history.

“Without a doubt, there will be more fatalities. We do not know, ultimately, how many will have occurred,” Governor Josh Green said on CNN on Friday.

Three days after the disaster, it remained unclear whether some residents had received any warning before the fire engulfed their homes.

The island includes emergency sirens intended to warn of natural disasters and other threats, but they did not appear to have sounded during the fire.

Officials have not offered a detailed picture of precisely what notifications were sent out, and whether they were done via text message, email or phone calls.

Maui County Fire Chief Bradford Ventura on Thursday said the fire’s speed made it “nearly impossible” for frontline responders to communicate with the emergency management officials who would typically provide real-time evacuation orders. He also noted that cellular service was knocked out.

“They were basically self-evacuating with fairly little notice,” he said, referring to residents of the neighbourhood where the fire initially struck.

Destroyed homes and buildings burned to the ground in Lahaina. Photo: Getty

The disaster began unfolding just after midnight on Tuesday when a brush fire was reported in the town of Kula, about 55 kilometres from Lahaina. About five hours later that morning, power was knocked out in Lahaina, according to residents.

In updates posted on Facebook that morning, Maui County said the Kula fire had consumed hundreds of acres of pastureland, but that a small (1.2-hectare) brush fire that cropped up in Lahaina had been contained.

By that afternoon, however, the situation had turned more dire. At 3.30 pm, according to the county’s updates, the Lahaina fire suddenly flared up. Some residents began evacuating while people, including hotel guests, on the town’s west side were instructed to shelter in place.

In the ensuing hours, the county posted a series of evacuation orders on Facebook as the fire spread through the town.

Some witnesses said they had little advance notice, describing their terror when the blaze consumed Lahaina in what seemed a matter of minutes. Several people were forced to leap into the Pacific Ocean to save themselves.

The Lahaina evacuation was complicated by its coastal location next to hills, meaning there were only two ways out, at best, said Andrew Rumbach, a specialist in climate and communities at the Urban Institute in Washington.

The island has six shelters in operation for the displaced, and officials said they were drafting a plan to house the newly homeless in hotels and tourist rental properties.

County officials said Lahaina residents would be allowed to return to check on their properties, but that a 10 pm curfew would be enforced. Much of Maui’s western side remained without power and water.

Tourists who were evacuated following wild fire destruction settle for the night as they wait for a flight to leave the island. Photo: AAP

‘Explosions everywhere’

“It was a vacation that turned into a nightmare,” recalled shaken survivor Vixay Phonxaylinkham, a tourist from Fresno, California, who escaped the flames with his family by taking refuge in the sea.

“We floated around four hours,” Mr Phonxaylinkham said at the airport while awaiting an evacuation flight.

“I heard explosions everywhere, I heard screaming, and some people didn’t make it. I feel so sad.”

Many more people suffered burns, smoke inhalation and other injuries.

“It was so hot all around me, I felt like my shirt was about to catch on fire,” Nicoangelo Knickerbocker, a 21-year-old resident of Lahaina, said from one of the four emergency shelters opened on the island.

Knickerbocker heard cars and a gas station explode, and soon after fled the town with his father, bringing with them only the clothes they were wearing and the family dog.

“It sounded like a war was going on,” he said.

Witnesses to the conflagration that hit Lahaina spoke of their terror as the blaze consumed a town in what seemed to be mere minutes.

Little warning of disaster

Hawaii emergency management records show no indication that warning sirens sounded before people ran for their lives in Lahaina.

Instead, officials sent alerts to mobile phones, televisions and radio stations – but widespread power and cellular outages may have limited their reach.

Hawaii boasts what the state describes as the largest integrated outdoor all-hazard public safety warning system in the world, with about 400 sirens positioned across the island chain to alert people to various natural disasters and other threats.

But many survivors said in interviews that they didn’t hear any sirens or receive a warning that gave them enough time to prepare and only realised they were in danger when they saw flames or heard explosions nearby.

Thomas Leonard, a 74-year-old retired mailman from centuries-old Lahaina, didn’t know about the fire until he smelled smoke.

Power and cellphone service had both gone out earlier on Tuesday, leaving the town with no real-time information about the danger.

He tried to leave in his Jeep, but had to abandon the vehicle and run to the shore when cars nearby began exploding. He hid behind a seawall for hours, the wind blowing hot ash and cinders over him.

Firefighters eventually arrived and escorted Leonard and other survivors through the flames to safety.

Fuelled by a dry summer and strong winds from a passing hurricane, at least three wildfires erupted on Maui this week, racing through parched brush covering the island.

The most serious one left Lahaina a grid of gray, ashen rubble, wedged between the blue ocean and lush green slopes.

Years to rebuild

Governor Josh Green said the scope of the disaster would surpass that of 1960, one year after Hawaii became a US state, when a tsunami killed 61 people on the Big Island of Hawaii.

“It’s going to take many years to rebuild Lahaina,” Green said at a news conference.

Lahaina’s 200-year-old Waiola Church was among the structures destroyed by the fire, local media reported.

The landmark was the focal point of Christianity on Maui and the burial site of early members of the Kingdom of Hawaii’s royal family, according to the church’s website.

The fate of some of Lahaina’s other cultural treasures remains unclear.

The historic 18-metre banyan tree marking the spot where Hawaiian King Kamehameha III’s 19th-century palace stood was still standing, although some of its boughs appeared charred, according to a Reuters witness.

Relief effort takes shape

Three Marriott hotels in West Maui were closed due to power outages, and guests have evacuated the properties, according to a company spokesperson. Some 12,400 homes and businesses were without power on Friday, according Maui County.

Volunteers formed human chains on Friday afternoon at Maalaea Harbor to transfer infant formula, nappies, clothes, fuel and other supplies onto boats.

Boat captains planned to sail around to the fire-affected areas and bring the supplies to the beach on jetskis, seconded from the area’s tourism industry, as the waters were choppy and docks had been damaged by the fires.

In a typical year, wildfires char less than one per cent of Hawaii’s acreage, about the same as other US states. But the spread of non-native, fire-prone grasses on former farmland around towns and a warming climate have elevated the threat of wildfires on the islands, according to the Hawaii Wildfire Management Organisation.

— AAP