A powerful winter storm that pounded Arizona with rain and snow prompted a search for a boy who was swept away by rising waters and is presumed dead, flooded an unknown number of homes and left several hikers stranded.

A search was under way early Friday for the 6-year-old boy who was caught in rising waters about 70 miles north of Phoenix near the community of Mayer. Dwight D'Evelyn, a spokesman for the Yavapai County Sheriff's Department, said the boy was presumed dead because a child isn't likely to survive such a flood.

MyFoxPhoenix: Entire Town of Wenden Underwater After Storm

In western Arizona, a 2-foot surge of runoff flooded streets and an unknown number of homes early Friday in Wenden, a community of 500 people located about 100 miles west of Phoenix. No one was reported missing or injured.

Seven hikers in Yavapai County also were stranded by high water, but were considered safe. Authorities had planned to try to reach the hikers after daybreak.

Forecasters said the storm reached its peak overnight Thursday, bringing high winds, heavy snow and rain that likely would flood parts of the state. Gov. Jan Brewer has declared a state of emergency.

"This is a monster storm, which is affecting much of the Southwest right now," said meteorologist Brian Klimowski in Flagstaff.

Travel on Interstate 17 between Flagstaff and Camp Verde, and State Route 89A between Flagstaff and Sedona is dangerous, forecasters said. Interstate 40 between Winslow and Kingman also was shut down.

Across metropolitan Phoenix, downed trees blocked driveways and palm fronds and other debris from the storm littered the streets.

The 6-year-old who is missing near Mayer was swept away as his family tried to take him to a hospital for treatment for a sickness. His mother and father loaded the boy and his 8-year-old sister into their pickup truck Thursday night. The flood disabled the truck and pushed it off the road.

The mother somehow made it to higher ground, while the father and two children got into the truck's bed. The three were swept from the bed. The father managed to get to safety with his daughter, but the boy remains missing.

In Wenden, earlier flooding from the storm receded late Thursday, but more water returned several hours later when a surge of runoff came through a nearby wash, said Lt. Glenn Gilbert, a spokesman for the La Paz County Sheriff's Office.

The flooding hadn't slackened by midmorning Friday. A crew in a Marine Corps helicopter was flying over the area in case anyone had been swept away or stranded. An unknown number of people were evacuated from their homes in Wenden.

Elsewhere in Yavapai County, seven hikers were stranded by high water, but were considered safe. Rescuers plan to reach them Friday.

At least two trailer parks near Black Canyon City were evacuated late Thursday and early Friday due to the rising Agua Fria River.

Flagstaff residents already digging out from nearly 3 1/2 feet of snow braced for another 2 feet or more of powder before the storm moves out Saturday.

The roofs on more than a dozen Flagstaff business were damaged early Friday under the weight of heavy rain and snow, but no injuries have been reported. The damage ranged from roof collapses at a fabric store and bookstore to leaky roofs at restaurants and compromised structural integrity at other buildings.

Farther south in Sedona and the Phoenix area, officials were preparing for flooding as water levels in rivers and creeks rose steadily.

The weather service reported early Friday that Oak Creek at Sedona crested below flood stage and no serious flooding was expected. It said that the creek at Cornville crested just below flood stage.

Flights at Phoenix's Sky Harbor airport were severely curtailed Thursday afternoon because of high winds from the storm, but they resumed late that night.

"Normal landing and departure procedures resumed," said airport communications center supervisor Kris Commerford. Major carriers were arriving and taking off, she said.