Boise, ID -

More than 450 square miles are on fire in Idaho, and some fire managers are nervous that predicted thunderstorms could cause that number to grow.

The National Weather Service issued a red flag warning for much of Idaho, with thunderstorms and lightning expected Thursday night and gusty winds on Friday.

Fire information officer Meghan Stump says crews are making good progress on the 172-square-mile Beaver Creek fire near Sun Valley. But the Little Queens fire near the small community of Atlanta continued to grow to 16 square miles, and Atlanta residents remain under a mandatory evacuation order.

Fire information officer Jennifer Costich says firefighters on the Incendiary Complex near Weippe are nervous about the impending storms, because wind could cause dangerous downdrafts or erratic fire behavior in north-central Idaho's canyons.