BOISE - Idaho 21 reopened to traffic Sunday evening, but fire officials are warning drivers to avoid the area if possible while crews battle a wildfire burning about 10 miles north of Boise.

The fire was first reported at about 4 p.m. Sunday near Robie Creek Road, prompting the closure of both lanes of Highway 21.

Officials say firefighters have halted the fire's growth at about 250 acres, although steep terrain and windy conditions had hampered their efforts for much of the day.

"We're also under a Red Flag Warning right now for the area for thunderstorms, so there's obviously going to be some gusty winds coming off of the storms as they pass over," said BLM spokesman Jared Jablonski.

The fire is expected to be fully contained by 9 p.m. Monday. No structures are threatened and there are no evacuations currently underway.

So far there is no word on what sparked the blaze.

Firefighters from IDL, the U.S. Forest Service and several rural fire departments are battling the fire from both the ground and the air.

While Highway 21 has reopened, travelers are being told to expect delays and temporary closures. Sunday evening, the Idaho Transportation Department said traffic was reduced to one lane, and a pilot car was leading traffic through the fire area.