Hawaii Attorney General Anne Lopez announced Thursday that she is engaging with a third party "with experience in emergency management" to conduct an investigation into last week's deadly wildfires.

"We intend to look at this critical incident to facilitate any necessary corrective action and to advance future emergency preparedness," Lopez said in a statement.

The attorney general said the independent review will likely be a "months-long effort," and the information collected by the third party will be "used to assess the performance in emergency preparedness as we are constantly looking for ways to improve."

Forty-percent of the impacted area on Maui has been searched, with the death toll remaining at 111, Maui County officials said Thursday.

The Olinda fire, Kula fire and Lahaina fire are 85%, 80% and 89% contained, respectively, officials said, adding that there are no active threats.

Electricity has been restored to more than 80% of the customers who lost power, officials said.

Emergency shelters housed 166 people overnight Wednesday, officials said. Another 279 people were relocated from shelters to hotels.

Residents heading to Lahaina to check on their homes are urged to be careful of the debris, as well as ash which could "contain toxic and cancer-causing chemicals including asbestos, arsenic and lead," officials warned.

In a pretaped message for ABC News' "Maui Strong" special on "Good Morning America," President Joe Biden promised the people of Hawaii that "the entire nation is with you as you recover, rebuild and grieve."

"We'll be with you for as long as it takes," he said.

"Already from the darkness and the smoke and the ash, we’ve seen the light of hope and strength," Biden said. "First responders working around the clock, many of those first responders in fact -- impacted by the fires themselves, losing their own homes. Volunteers delivering aid by fishing boat, ferry, on jet skis. Chefs whose restaurants were destroyed, cooking food for displaced families."

Biden said that when he and the first lady visit on Monday they will "convey in person our grief and solidarity and commitment to the people of Maui."

-ABC News' Justin Gomez

FEMA Administrator Deanne Criswell, who has toured the devastation on Maui, told ABC News' "GMA3" that "it really just seems so much more worse once you see it in person."

She called it a "really complicated search and recovery mission," adding, "It's going to be a complicated debris removal mission once we account for everybody that's missing."

Criswell said FEMA is working closely with state partners and the American Red Cross to find shelter for displaced residents.

"We're already working on what the long-term housing is going to look like," she said Thursday. "We convened yesterday at the White House with all of the deputy secretaries from the Cabinet-level agencies to talk about resources that we can bring in."

"We're putting every resource available and creative solutions to come up with ways that we can help Maui and help the government of Hawaii," Criswell continued. "When I talked to the governor, he already had started a housing assessment based on the limited housing that they have. This is going to be a really great starting off point for us to help implement some of the vision he had and use that planning to help with the long-term recovery housing issues."

There have been at least six deaths reported in Maui County amid devastating wildfires, officials said.

"We're still in a search and rescue mode, and so I don't know what will happen to that number," Maui County Mayor Richard Bissen said during a press briefing Wednesday afternoon.

More than 2,100 people are in shelters in Maui County, he said.

Shelters are "overrun" amid the disaster, Hawaii Lt. Gov. Sylvia Luke said while urging tourists not to travel there.

"This is not a safe place to be," she said.