The area’s first notable wildfire of 2018 was reported about 50 percent contained Thursday morning, following two days of zero growth and a sustained air and ground attack.

“Things are looking very good,” said Beau Macy, District Assistant Fire Management Officer with the U.S. Forest Service in Troy, of the 20-acre Zulu fire in the Yaak north of Libby.

The fire is not threatening any structures, he said.

Officials believe the fire was caused by lightning on June 11 and smoldered undetected until the morning of Sunday, July 15, when a lookout on Swede Mountain reported it, said U.S. Forest Service Ranger Kirsten Kaiser of Three Rivers Ranger District in Troy.

The fire reached 10.5 acres by Monday morning and 20 acres by Tuesday morning before holding steady.

About 80 Forest Service and DNRC personnel from four crews are fighting the fire from the ground, Macy said, while an assortment of helicopters and single-engine air tankers have been steadily attacking it from above.

Two firefighters were injured Tuesday evening, one suffering from heat exhaustion and the other from a “pre-existing condition” that Kaiser did not specify. Both were flown to regional hospitals and in “good shape” by Wednesday morning, she said.

A Forest Service Type III team assumed command of the fire by Wednesday morning, according to Forest Service spokesperson Willie Sykes.

Thursday morning, Macy reported a “little bit of a lull” in weather that had been hot, dry and breezy. Higher nighttime relative humidity coupled with less wind made conditions more favorable for firefighting, though Macy anticipated winds would pick back up within a day or two.

“We should have it looking pretty good before they hit,” he said.

Macy also noted that, despite the lull, fire danger in the Kootenai National Forest remained “very high.”

No additional injuries have been reported, he said.