A wildfire that has been burning in central Idaho for 12 days continues to threaten the popular ski resort of Sun Valley:

More than 1,200 people and 19 aircraft were battling the lightning-caused Beaver Creek Fire, which started Aug. 7 and was 9 percent contained. Nearly 90 fire engines also were in the region, many protecting homes in the affluent area where celebrities like Arnold Schwarzenegger, Tom Hanks and Bruce Willis own pricey getaways.

Hartman said Sunday retardant was being dropped on the flank of Bald Mountain — the Sun Valley Resort’s primary ski hill — to reinforce a fire line. That meant the famed ski mountain known as “Baldy” and often used in publicity photos would have a red line of retardant visible from Ketchum.

[Spokeswoman Shawna] Hartman said the drop was part of a plan by fire managers to bolster protection for the tony resort town, but he noted the fire had not yet spread to the mountain.

Associated Press

By Sunday night, the fire had burned just over 100,000 acres and was 8 percent contained. For the most recent information, visit this official page. The fire has burned fiercely and unpredictably, alarming firefighters and others:

Wildfires generally subside overnight, Hartman said, but this one “picked up intensity and even made a run, which is very uncommon.” The overnight activity strengthened an already unpredictable blaze, which officials said had been jumping with little warning from ridge to ridge and burning in all directions with equal intensity.

Hartman attributed the fire’s behavior to wind gusts topping out at 30 mph, low humidity, dry ground fuels and the area’s curvy topography.

The fire’s proximity to homes has provoked a robust and coordinated response in a region familiar with big blazes. Private insurance companies have sent in their own engine crews to bolster structural protection for homes that can cost millions of dollars, [Blaine County spokeswoman Bronwyn] Nickel said.

In addition, Sun Valley Resort has turned on water cannons, normally used to make snow in the winter, in order to keep grass and trees moist. The Sun Valley area is under preevacuation orders.

Benjamin Mueller, Los Angeles Times

Other fires have forced evacuations in northern Utah. Three more are burning near The Dalles in Oregon:

All three fires were sparked by lightning strikes Friday, and had grown to around 1,500 acres by late Sunday, pushed along for 30-plus mph winds, said Oregon Dept. of Forestry spokesman, David Morman.

Oregon is experiencing what is shaping up to be the worst fire season in more than a decade, Governor John Kitzhaber said last week, thanks to a rash of lightning storms and unseasonably dry forests.

Stuart Tomlinson, The Oregonian

For scenes from the Beaver Creek fire in Idaho, watch the CBS News broadcast below.

A wildfire burning near resort communities in Idaho has burned more than 100,000 acres.