Yellowstone fire grows to 515 acres

YELLOWSTONE NATIONAL PARK, Wyo. – Nearly 170 firefighters are battling a 515-acre wildfire burning in the backcountry near the center of Yellowstone National Park. Cooler, more humid weather Wednesday helped firefighters who are building control lines around the west and southern edges of the fire, which is about 20 percent contained. Officials don’t know yet how the fire started.