In northern Utah, about 10 homes were destroyed when a wildfire raced through the community of Willow Springs late Friday, jumping a state highway and fire lines, authorities said.
As of midday Saturday, the Patch Springs Fire had burned more than 50 square miles. It was 20 percent contained.
In Idaho, the Beaver Creek Fire grew by 15 square miles late Friday and early Saturday, to 144 square miles. Overnight, flames moved closer to homes and subdivisions in the mountains west and north of the communities of Hailey and Ketchum and the Sun Valley Resort.
So far, authorities have issued mandatory evacuations for 1,600 residences in the valley, which serves as a vacation getaway for celebrities like Arnold Schwarzenegger and Tom Hanks.
The blaze was started by lightning Aug. 7. It expanded significantly Friday, burning through tinder-dry brush and timber in the mountains west of the towns. Efforts Saturday were focused on protecting homes and structures in the gulches and foothills just west of Hailey and Ketchum.
Crews also planned to target erratic, wind-driven fire growth in one area north of Ketchum and two locations west of Hailey.
Heavy smoke that grounded firefighting aircraft early Saturday cleared enough to allow helicopters and a huge DC-10 tanker to start making drops in the afternoon.
Fire managers and more than 700 firefighters braced for another dose of hot temperatures and afternoon wind gusts up to 30 mph that could move flames closer to homes. Hundreds more firefighters were expected to arrive Saturday.
"This fire is consuming everything," fire spokeswoman Madonna Lengerich said. "The fire is so hot, it's just cremating even the biggest trees."
