Emergency crews are working under hazardous conditions, officials said, after the deadliest wildfires in the United States in more than a century first broke out last week.

Thousands of survivors have been displaced by the blazes, the worst of which destroyed much of the historic town of Lahaina, and people across Maui have put out desperate pleas for information about missing loved ones.

Here is what we know about what caused the fires, the breadth of the destruction and what comes next:

How did the fires start?

The exact cause of the blazes has not been determined. But with much of the world seeing record-breaking temperatures during a global climate crisis, wildfires have become more frequent and more difficult to contain.

The National Weather Service had issued warnings for the Hawaiian islands due to dry weather and high winds linked to Hurricane Dora, which was passing through the area. Both are often catalysts for wildfires.

While most wildfires are started by human activity, natural causes – including lightning and volcanoes – can also spark blazes.

Governor Josh Green said the state was experiencing dry conditions due to climate change and, with a major storm passing south of the state, multiple blazes began to spread quickly and uncontrollably in what he called a “fire hurricane”.

“That’s what a fire hurricane is going to look like in the era of global warming, and so we have to all do – right now, right now – what we can to stop global warming and reverse it,” he told MSNBC on Sunday.

How many people have been killed?

Officials have so far confirmed the deaths of 96 people, but they said that figure will rise.

Green said on Monday that search teams working with cadaver dogs will need more time to survey burned-out homes and vehicles in the hard-hit town of Lahaina.

“They will find 10 to 20 people per day probably until they finish. And it’s probably going to take 10 days. It’s impossible to guess, really,” the governor told CBS News.

Deanne Criswell, the head of the Federal Emergency Management Agency (FEMA), told reporters that the search effort is challenging due to partially standing structures, high temperatures and “hot spots” of isolated fires.

Firefighters are still battling flare-ups, officials said, with the largest fire in Lahaina mostly contained.

“We want to make sure that we’re doing this as quickly as possible but that we do it in a way that’s methodical and appropriate and culturally sensitive to make sure that we are going to be able to account for everybody,” Criswell said.

Did people receive a warning?

Hawaii has a large network of sirens designed to alert residents about natural disasters and human-caused events, but many people on Maui have reported that they did not receive any warnings as the fires quickly approached.

“You know when we found that there was a fire? When it was across the street from us,” resident Vilma Reed, 63, told the AFP news agency.

Sirens stationed around the island never sounded, residents have said, and widespread power and mobile service outages hampered other forms of alerts.

As the wind-propelled blazes rapidly advanced, people were forced to abandon their homes and vehicles to seek safety. Some even dove into the Pacific Ocean to try to escape the flames.

Hawaii Congresswoman Jill Tokuda told CNN that officials had been taken by surprise by the tragedy. “We underestimated the lethality, the quickness of fire,” she said.

Green said he has ordered a “comprehensive” review of the state’s response. He also said the fast-spreading blazes destroyed telecommunication towers.

FEMA’s Criswell referred questions about the issue to state officials. “As an emergency management and first responders’ community, we always want to look at the lessons learned so we can improve,” she said.

Where are survivors staying?

FEMA and aid groups have opened emergency shelters for thousands of people who have been displaced by the blazes.

Criswell also said FEMA has activated a programme to move evacuated people from shelters to hotels.

Todd James, an official with the American Red Cross, said the organisation has also been helping connect residents with housing resources. “It could go on for a long while,” James told Al Jazeera of the housing issue.

“We will work with both our partners – our governmental partners, our nonprofit partners and most importantly with the families themselves – to help them find what the next step from the shelter is.”

What has President Biden said?

President Joe Biden has pledged to make resources available for Hawaii, including temporary and long-term housing, direct assistance and help to locate missing people.

“As residents of Hawaii mourn the loss of life and devastation taking place across their beautiful home, we mourn with them. Like I’ve said, not only our prayers are with those impacted – but every asset we have will be available to them,” Biden wrote in a social media post on Monday.

How does this compare to other US wildfires?

The Maui blaze is the deadliest US wildfire since 1918 when northern Minnesota’s Cloquet Fire, which raged for more than four days, killed 453 people, according to the National Fire Protection Association.

The deadliest wildfire in US history, Wisconsin’s Peshtigo fire in 1871, killed 1,152 people.

Hawaii’s fires also constitute the most lethal disaster to hit the islands since a tsunami that killed 61 people in 1960, a year after Hawaii became a US state.