Crews critically needed medium-sized helicopters, he said. With 23 uncontained large fires or fire complexes in Nevada, Utah and southern Idaho alone, there aren't enough contractor-supplied helicopters to go around, he said.

"It's really competitive right now to get those (helicopters)," Frederick said.

Thursday morning brought slightly lower temperatures in the Northwest, Frederick said, but the break wasn't expected to last long. Dry, windy weather, temperatures reaching above 100 degrees and thunderstorms are predicted for the next seven days, he said.

Eighteen miles southeast of Boise, the Wood Creek fire was burning on nearly 4 square miles of grass and brush-covered Bureau of Land Management property. Though still relatively small, the lightning-sparked fire was racing toward Danskin Mountain where fire managers feared it would threaten lookout towers and other buildings, BLM spokeswoman Jessica Gardetto said. But with all the other fires burning in the region, BLM was having trouble tracking down extra crews to fight the blaze.

"We're drafting for more hand-crews and more resources — we'd like to get another helicopter because it's in really steep terrain — but no one has them to give right now," Gardetto said.

In Nevada, crews Wednesday battled more than two dozen fires burning across 312 square miles of rangeland and timber in the northern part of the state. One threatened hundreds of homes on the edge of Reno.

The largest wildfire in Oregon, near Burns in the southeast portion of the state, had grown to more than 200 square miles and was threatening a handful of homes, officials said.

In Utah, two new large fires were reported, in addition to three already burning on about 640 square miles of grass, sage and timber. It was so dry there that some Utah communities banned traditional July 24 fireworks that members of the Church of Jesus Christ of Latter-day Saints normally shoot off to celebrate the 1847 arrival of Mormon pioneers in the Salt Lake Valley.

In Southern California, authorities were trying to stop a 43-square-mile wildfire from spreading toward about 50 scattered homes in Los Padres National Forest in the interior of Santa Barbara County. In Northern California, overnight drizzle helped firefighters battling flames that threatened more than 300 homes in and around Happy Camp in the Klamath National Forest near the Oregon border.

Fires in Eastern Washington eased Wednesday when thunderstorms brought welcome rain, allowing some firefighters to be redeployed.