Rain showers and increased humidity during the weekend had helped crews keep the nearly 29-square-mile fire from spreading.
On Monday, however, afternoon thunderstorms were expected to produce wind gusting as high as 50 mph, fire information officer Michelle Fidler said. There was already enough wind early Monday to carry smoke from the blaze 90 miles north to Salt Lake City.
The fire started Thursday and remained about 15 percent contained Monday, Fidler said.
The small towns of Oaker Hills, Indian Ridge, Elk Ridge, Indianola and Holiday Oaks had been evacuated, officials said. Ricardo Zuniga, a spokesman for the Federal Emergency Management Agency, said a shelter was set up at a school in Mount Pleasant.
Dozens of other fires burning in nine western states have scorched about 1.5 million acres, reports CBS News correspondent Sandra Hughes. Officials have the nation at its highest preparedness level with foreign and National Guard resources ready to move in.
The large fires are primarily in Idaho, Nevada, Oregon and Utah, the National Interagency Fire Center said Monday. Fire managers were worried that dry lightning storms in some of those states could spark further blazes, though the systems were expected to bring rain Tuesday, the agency said.
A wildfire in southern Idaho had covered more than 880 square miles, growing by about 200 square miles in just 24 hours during the weekend. Devouring grass and brush and helped by super-dry fuels and triple-digit temperatures, the blaze is moving rapidly and is not easily fought, reports CBS News correspondent Stephen Kaufman.
Fire officials said it threatened tracking and radar facilities at Mountain Home Air Force bombing and firing range, which is used by pilots training for duty in Iraq and Afghanistan.
"That fire was just so large, and it's in remote territory," Rich Ochoa, spokesperson for the National Interagency Fire Center, told CBS News. "It's not real flat land. There are lots of hills and canyons and so on."
Mandatory evacuations remained in effect for the tiny town of Jarbidge, Nev.; an evacuation order for Murphy Hot Springs was lifted for residents only. A lot of grazing land burned, and cattle likely died in the fast-moving blaze, fire spokeswoman Pam Bierce said.
In northern Idaho, a lightning-caused fire had raced across 31 square miles and destroyed nine buildings at a hunting outfitter's ranch, fire spokesman Chuck Stanich said.
A fire in and around Zion National Park in southwestern Utah was nearly halfway contained Monday after burning 14 square miles.