GRACE — Fire officials expressed strong confidence Monday that firefighters have gained the upper hand on the McPherson Fire east of Grace, even as updated mapping revealed the blaze is considerably larger than previously reported.

The wildfire is now estimated at 298 acres, up from the 225-acre figure reported over the weekend, according to the Eastern Idaho Interagency Fire Center. Officials attributed the increase to more accurate mapping rather than new fire growth.

Fire officials estimated the blaze would be fully contained by 6 p.m. Monday, with full control expected by 6 p.m. Wednesday.

All roads and trails in the fire area were closed Sunday and will remain closed until further notice, officials said.

There have still been no injuries, evacuations or damage to structures. Homes and outbuildings near the fire remain considered threatened as of Monday morning, though they are not in any immediate danger, authorities said.

Officials have determined the fire was human-caused and said the cause remains under investigation, with no further details released.

Resources on scene as of Monday included roughly 100 personnel, six fire engines, a bulldozer and two firefighting helicopters. Federal firefighters are battling the blaze alongside crews from Bear Lake and Caribou county fire departments.

No air tankers were expected to fly Monday, but the two helicopters continued running sorties against the fire.

The blaze ignited early Friday evening in McPherson Canyon and quickly grew to more than 200 acres. But federal and local firefighters have been able to keep the fire in check, thanks to the fire-resistant maple trees in the fire area, as well as timely retardant drops from air tankers Friday and Saturday.