Western Montana’s air quality degraded Monday morning as smoke from large wildfires in Washington and Oregon infiltrated the region.

The blanket of haze caused moderate air quality levels from the Flathead Valley to Missoula, Bozeman and Billings.

Forecasts suggested the smoky weather would continue into Tuesday, while northeast Montana could see moderate to heavy smoke from wildfires north of the border.

“Not only will the region contend with domestic smoke this week, but Canadian wildfire smoke will sag south of the border,” the Montana Department of Environmental Quality wrote in its Monday forecast.

At least 20 named fires were active across Washington and Oregon on Monday, with the largest having charred 92,000 acres in north-central Oregon. A cluster of fires west of Spokane, Washington, had burned more than 65,000 acres.

Western Montana’s wildfire activity remained limited to a 33-acre blaze burning on Forest Service land west of Olney. Two helicopters and a bulldozer were assigned to fight the fire along Adent Creek, which started after Friday night’s lightning storm.

North of Libby, the Tub Gulch Fire was listed at one-tenth of an acre and under control. A firefighting helicopter pulled water from the Kootenai River to drop on the fire.

Two fires were active in the northern Idaho Panhandle. The Turner Fire had burned 681 acres north of Bonners Ferry, while the lightning-caused Upper Smith Fire near the Canadian border was estimated at 748 acres.

Elevated fire danger is expected later this week as hot, dry weather settles over the northern Rockies. High temperatures in the Flathead Valley will reach the 90s from Wednesday through Friday.

“The combination of warm temperatures, low humidity and gusty winds will create dangerous fire weather conditions across Montana,” the DEQ forecast warned. “Despite a slow start to the wildfire season in Montana, this could set the stage for a smoky end to July.”