An expected increase in winds along with warm, dry weather has firefighters bracing for more active wildfire growth in Yellowstone National Park.
There are five fires burning in the park, but all major tourist attractions and park roads remain open.
Fire spokesman Bill Swartley says all the fires are growing and critical fire conditions are expected into Friday.
The largest fire, which is located north of the West Entrance Road between West Yellowstone, Montana, and Madison Junction, has burned about 57 square miles.
Since it was started by lightning on Aug. 8, it has been allowed to burn. But now the fire is getting so big that firefighters are starting to take action to keep it from places like Madison Junction or burning outside the park boundary.