(Recasts to show wind aiding firefighters; evacuation orders lifted for 400 homes)
By Laura Zuckerman
SALMON, Idaho, Aug 19 (Reuters) - Firefighters, aided by subdued winds, pressed their tactical advantage for the second day of a major air and ground offensive against an Idaho wildfire that has forced the evacuation of more than 2,000 homes near the world-class ski resort of Sun Valley.
Part of the firefighting assault on Monday, day 12 of the so-called Beaver Creek blaze in central Idaho, focused on the famed ski slopes of Bald Mountain, where snow-making water cannons have been saturating the hills.
Ground crews backed by bulldozers and helicopters dumping payloads of flame retardant worked to reinforce an extensive fire break running from the top of the mountain down its southeastern face to keep the blaze from advancing into the adjacent tourist town of Ketchum.
"That's our insurance policy for Ketchum," fire information officer Rudy Evenson said. From a distance, parts of the slope were stained red from the slurry drops.
Elite firefighting teams armed with hand tools and chain saws battled to knock back a flank of the fire south of Ketchum that posed the greatest immediate threat to the community.
Farther south, authorities lifted mandatory evacuation orders for 400 homes in four neighborhoods near the larger resort town of Hailey. But Blaine County Sheriff Gene Ramsey warned returning residents they should be prepared to flee again at a moment's notice.
Firefighters seized on the opportunity to keep up their aggressive attack as calmer winds and higher humidity prevailed for a second day, contributing to diminished flames.
The fire has charred some 104,000 acres (42,087 hectares) of parched sagebrush, grasslands and pine forests in the Sawtooth National Forest since it was sparked by lightning on Aug. 7.
More than 1,100 firefighters have been assigned to the blaze, whose ever-shifting nature has vexed fire managers. Containment, the portion of the blaze's perimeter firmly enclosed by fire breaks, remained at less than 10 percent.
AREA CONTAINS CELEBRITY HOMES
Beth Lund, incident commander with the U.S. Forest Service team managing the blaze, expressed cautious optimism on Sunday about prospects for gaining control over the blaze.
"I think we're getting to the point where we can start making some progress rather than just be on the defensive," she said. "But when Mother Nature feels she has the upper hand, she keeps it for a while."
At its peak, the blaze was threatening more than 5,000 residences, 1,400 commercial structures and some 3,700 outbuildings, forcing the evacuation of at least 2,250 homes in posh developments outlying Sun Valley, Ketchum and Hailey.
Authorities put the value of endangered land and property in the region, known as the Wood River Valley, at roughly $8 billion. The area contains homes belonging to celebrities such as film director Steven Spielberg, actor Tom Hanks and singer and actress Barbra Streisand.
The blaze has spewed thick smoke over an area prized for scenic views, mountain lakes and a river teeming with wild trout.
Scores of residents and tourists fled over the weekend from Sun Valley and Ketchum, where streets - and many homes - were largely deserted after authorities issued stand-by notices for possible evacuations there on Friday night.
The Beaver Creek fire is one of dozens raging across several western states in a fire season that has already brought substantial property losses and a higher-than-normal number of firefighter deaths, including 19 in a single Arizona blaze. (Reporting and writing by Laura Zuckerman; Editing by Steve Gorman and Dan Grebler)