Having toured the flooded area by air Monday, Napolitano told reporters the most important task was to restore a pack trail that is a main path for delivering mail, food and other supplies to villagers at Supai.
Attention is now being turned to rebuilding and repairing trails into and around the remote Havasupai Tribe village, about 30 miles west of Grand Canyon Village. It's an 8-mile hike from the nearest parking lot, dropping straight down on a winding canyon trail, about 2,300 feet below the Grand Canyon rim. It's the only community in America where the mail is delivered by mule.
The village itself includes homes, a K-8 school, a post office, a cafe, clinic and a store. It sits in a region that's popular for hikers and river runners, with towering blue-green waterfalls. About 400 people live there year-round.
Supai and the surrounding area got soaked over the weekend as thunderstorms dumped 3 to 6 inches of rain Friday and Saturday in northern Arizona and about 2 inches more on Sunday.
Helicopters on Monday took turns ferrying 85 people out of Supai. Rescuers transported another 170 people out of Supai Canyon on Sunday.
Village residents asked for extra supplies Monday, but Coconino County Sheriff's Department spokesman Gerry Blair said authorities weren't sure yet what to deliver. It's unclear how much Supai will need since many residents are choosing to leave the village, and authorities don't know how long it will take to reopen hiking trails to the public.
Over the weekend, dozens of tourists were stranded as rushing water swept away rafts, backpacks, food and other supplies. Some hiking trails and footbridges were washed out and trees were uprooted.
"It was definitely frightening, and there was a lot of, 'Whoa, what are we going to do next and what's the morning going to bring?'" said Mimi Mills, 42, of Nevada City, California, who was stranded with 15 other river runners Saturday afternoon after a flash flood washed away their rafts.
Mills said the group took shelter overnight under an overhang, but had to scramble up a cliff when another flash flood occurred in the middle of the night.
"I woke up to people yelling, 'We've got to get out of here!'" she said. "We booked it up a cliff in 10 seconds, and we just saw this massive rush of water rage down the creek side."
In another part of the canyon, an earthen wall that forms a pond to water cattle and other livestock was breached about 45 miles upstream from Supai.
Havasupai Vice Chairman Matthew Putesoi declined to comment until the tribe checks the extent of the damage to the village. No more tourists were being allowed in.
Ferdinand Rivera, who was visiting the canyon with friends, awoke around midnight Saturday to the voices of other campers warning of rising flood waters that were approaching his tent.
Within 10 minutes, he said he gathered his tent and belongings and sought higher ground. But with a nearby bridge and trails washed out, he said "there was no way of hiking back, there was no way of getting out."
With his gear in tow, he hiked about 2 miles (3 kilometers) across rugged ground to the village where he was evacuated by helicopter Monday afternoon.
Rivera said officials should have forced evacuations sooner and worked quicker to remove those who were stranded in the canyon. "It was so negligent, so badly handled not only by the villagers but also by whatever agency was there, that I will never go back to that place," he said.
The Havasupai tribe is one of the smaller Indian communities in Arizona with about 679 members, according to Bureau of Indian Affairs estimates from 2003, the latest statistics available.