A wind-driven blaze tore downslope across the Wind River Range foothills Sunday and Monday, quickly chewing up enough acreage to become Wyoming’s largest wildfire of the year.
The Weiser Knoll Fire ignited on Sunday afternoon due to a mechanical fire on a trailer being towed, Fremont County Fire Protection Chief Ron Wempen told County 10 News. Within hours, the blaze was throwing up a smoke column and quickly burning through sagebrush and grasslands on South Pass — and it didn’t let up once darkness fell.
“It burned fairly active all night,” said Jerod DeLay, Wyoming’s fire management officer. “There was some pretty extreme fire behavior yesterday, with the dry fuels and the wind and low humidity.”
Trying to keep the fire west of Twin Creek Road, wildland fire crews conducted controlled fire operations and “for the most part were successful,” DeLay said.
As of midafternoon Monday, the fire perimeter also remained confined to an area east of Wyoming Highway 28 and south of U.S. Highway 287, according to Fremont County Emergency Management Coordinator Milan Vinich.
Nevertheless, the Weiser Knoll Fire’s estimated acreage grew dramatically over its first 24 hours and reached 13,350 acres with no official containment by 3 p.m. on Monday. Winds gusted to 41 mph in nearby Lander that afternoon, and a Red Flag warning — which means there are “critical fire conditions” — remains in effect until 9 p.m. Tuesday, increasing the likelihood for growth.
A Fremont County evacuation order remains in place for the Twin Creek drainage and portions of South Pass.
The new U.S. Wildland Fire Service is taking the lead on the fast-growing wildfire, trying to extinguish it with a “type 3” incident management team. An estimated 85 personnel committed to the 21-square-mile blaze and a handful of aircraft have also assisted, including multiple helicopters and large and small fixed-wing air tankers.
Wyoming State Forestry also dispatched its new Lander-based wildland firefighting team to help combat the Weiser Knoll Fire. The team was diverted from the 443-acre Bare Fire in the Wyoming Range, DeLay said.
In the hours after the conflagration began, engines from all over Fremont County swarmed on South Pass to try to tamp down the fast-moving front of flames.
“You had Jeffrey City, Lander, Hudson and Fremont County battalions 1, 4, 5, 12, 3, 9, and 10 on it,” Vinich told WyoFile. “BLM, U.S. Forest Service and BIA engines were also involved.”
Wyoming so far in 2026 has mostly dodged the massive wildfires that have plagued other parts of the intermountain West. Neighboring Utah has already broken its state record for wooded and forested acres burned, the gargantuan 550,0000-acre Big Grass Fire is burning along the Oregon-Idaho state line and year-to-date acreage burned across the country is more than 50% above average and the most in at least a decade, according to the National Interagency Fire Center.
Wyoming has had an active year, too. But the Weiser Knoll Fire is the largest incident of the year, surpassing Sheridan County’s Lumin Fire, which was extinguished in late July.
“We’ve been pretty successful this year,” DeLay said. “Most of the fires have been one, two or three day events, so we’ve been pretty fortunate that way.”
