Two stubborn fires that consumed 700 acres continued to smolder Monday as crews soaked down the embers, while fire bosses planned for a hopping Labor Day weekend.

The 500-acre Powder Mountain fire east of Ogden was contained at 6 p.m. Sunday with control expected on Tuesday, Interagency Fire Center dispatcher Frank Williams said.Fire investigators were trying to determine whether a bulldozer from the ski resort started the fire last week, and whether penalties would be assessed, Williams said.

The fire started on private land and then spread to federal and state property. About 40 firefighters were on the scene Sunday.

Crews also were mopping up the remains of a 200-acre fire in the Ashley National Forest, officials said.

"We have demobilized most of the resources on the fire, and we have one crew and three engines that are staying there to control and complete mop-up on that. It's looking very good," said Dennis Jensen, planning section chief.

The fire, believed to be caused by arson, charred lodgepole pines that had been killed by pine beetles. The dry timber made suppression of the fire difficult.