YOSEMITE NATIONAL PARK, Calif. — Visitors trying to photograph Yosemite National Park’s famed peaks yesterday instead took shots of flying ash blowing in from an out-of-control wildfire burning just 12 miles outside the park.

The fire — which has destroyed 25 homes and is only 15% contained — has shrouded one of California’s most popular destinations in smoke, and risks marring business at the height of Yosemite’s busiest season.

Authorities said yesterday the blaze had charred more than 46 square miles of steep, rugged terrain since a target shooter sparked the wildfire Friday.

It has also forced the evacuation of 300 homes in the towns of Midpines and Coulterville, gateway communities whose businesses rely on tourist dollars.

Fire crews are expected to get some help from a slight drop in temperature, which was forecast to remain in the high 80s yesterday, accompanied by low humidity and afternoon winds, the National Weather Service said.

At summer’s peak, as many as 4,000 visitors a day stream into the park, and rangers expect the fire will keep very few people away.

Visitors seeking to enter the park from the west were turned around yesterday, when authorities temporarily shut down a 10-mile stretch of Highway 140 to keep flames from leaping across the Merced River canyon. Limited electricity was restored Tuesday in the community of El Portal, near the park’s western boundary.

Elsewhere, fire officials at Red Lodge, Mont., said yesterday that evacuation of an additional 200 homes west of the ski resort town was likely because strong wind threatened to push a wildfire closer to the area.