(Updates with more evacuation orders, details on fire)
By Laura Zuckerman
SALMON, Idaho, Aug 16 (Reuters) - Firefighters battled on Friday to check a fast-moving wildfire raging near the Sun Valley ski resort in Idaho, where hundreds of people were evacuated as flames menaced multimillion-dollar homes in the area, authorities said.
The so-called Beaver Creek Fire, now the nation's top firefighting priority, has raced across 64,000 acres (25,900 hectares) of mountains and canyons intersected by luxury housing developments since it was sparked by lightning in the Sawtooth National Forest on Aug. 7.
Occupants of more than 600 dwellings have been ordered to evacuate and the tourist towns of Ketchum and Sun Valley have been told to be ready to leave at a moment's notice, said Blaine County spokeswoman Bronwyn Nickel.
The fire is one of dozens of destructive blazes in Western states, many of them fed by drought conditions, unusually high temperatures and fierce winds.
On Friday near the Idaho ski resort, in the state's Wood River Valley, plumes of smoke towered over the area, at the height of a summer recreation season that drives the local economy.
U.S. Forest Service and other fire crews had lost ground against the blaze by Friday morning, with a containment estimate of 11 percent on Wednesday dropping to 9 percent.
One flank of a blaze edged closer on Friday to Ketchum, just minutes from the community of Sun Valley and its namesake ski resort, which fire officials said faced no immediate threat.
In the towns of Hailey, Ketchum and Sun Valley, foot traffic was light as thick smoke reduced visibility and hampered driving on the only highway that connects the three communities.
ROADWAY UNDER THREAT
Cars and trucks streamed down the roadway, which the local sheriff warned may close with the fire's approach, as residents of Ketchum and Sun Valley sought refuge elsewhere.
Dale Byington, general manager of the Sawtooth Club, an award-winning restaurant in Ketchum, estimated that 70 percent of the city's roughly 2,700 residents have fled. He described the largely deserted downtown as "surreal."
Byington said he had packed belongings into his vehicle and was ready to leave if flames continue to advance.
"It's not good," he said.
Air tankers were assigned to drop fire retardant near clusters of upscale homes nestled in subdivisions between Hailey and Ketchum, and fire engines were deployed to guard luxury residential developments where homes can be worth tens of millions of dollars.
The fire on Thursday night destroyed one house in an outlying neighborhood, Nickel said. She added that insurance companies have dispatched teams of contractors to protect high-end homes.
Elsewhere in Idaho, fire crews were gaining ground on a blaze menacing two mountain resort towns in the Boise National Forest about 70 miles (113 km) east of the state capital. The so-called Elk Complex fire near Pine and Featherville has consumed 38 houses and 43 other buildings outside city limits.
The 117,000-acre (47,350-ha) blaze has killed dozens of animals - including elk, deer and a black bear - since it was ignited by lightning on Aug. 8. Featherville and Pine, where Idaho Governor C.L. "Butch" Otter has a getaway cabin, have been mostly emptied of hundreds of summertime residents.
Otter and U.S. Forest Service chief Tom Tidwell were expected to tour the two wildfires by air on Friday. (Editing by Cynthia Johnston and Eric Walsh)