DULUTH – A 40- to 70-acre wildfire was burning in Carlton County about 45 miles southwest of Duluth.

Planes dropped water to douse the flames Monday evening, soon after the fire was detected near Barnum. They returned Tuesday to continue work after the fire reactivated, said Leanne Langeberg of the Minnesota Interagency Fire Center in Grand Rapids.

She said no evacuations or road closures have been ordered, but nearby structures are threatened as crews worked to build containment lines. Langeberg said the fire was most active in the area of County Roads 8 and 11, 10 miles southeast of Barnum on the eastern side of Interstate 35.

The Minnesota Department of Natural Resources and fire departments from Barnum, Carlton, Blackhoof and Moose Lake are involved in firefighting efforts.

Rain is expected in the region but "it won't pull us out of concerns that have been building since this spring," Langeberg said. "It'll take measurable rainfall over some time for that to finally build back up. The vegetation is pretty stressed this year."

The U.S. Drought Monitor says Carlton County is dealing with extreme drought this week. Parts of northern Minnesota experienced record high temperatures over the weekend, with the Barnum area reaching nearly 100 degrees on Labor Day.