Fire investigators from across the country are in Prescott, Ariz., trying to determine what caused the nation's largest loss of firefighters since 9/11.
Meanwhile, thousands gathered Tuesday night for a vigil honoring the 19 members of the Granite Mountain Hotshots who died in the blaze.
Among those present was 21-year-old Brendan McDonough, the sole survivor of the 20-person crew of elite firefighters.
McDonough was acting as a lookout when the winds suddenly shifted and the fire raced out of control Sunday.
"He's trying to deal with the same things that we're all trying to deal with, but you can understand how that's compounded being there on the scene," Prescott Fire Department spokesman Wade Ward told reporters at an evening news conference.
"He was warning them to get out," he said. "They had made their plan to get out and they were attempting to reach their safety zone."
There are still nearly 600 firefighters on the front lines of the blaze that has scorched more than 13 square miles and destroyed 200 homes.