After weeks of intense suppression work, the Tartar Fire burning in Washington County, Idaho north of Weiser has reached 87% containment at 158,027 acres. The fire, which erupted in late July and ran more than 20 miles in a single night toward Weiser — impacting structures along US Highway 95 — has been one of the most dramatic and destructive fires of the 2026 season in southern Idaho.
Fire Origins and Rapid Spread
The Tartar Fire ignited in Washington County's rangelands and quickly spread into a fast-moving, wind-driven grass fire. On the night of August 2, the fire ran approximately 20 miles in a matter of hours toward the city of Weiser, a community of roughly 2,400 people in the Snake River Valley. The fire impacted structures and burned hay stores along US Route 95 before crews were able to slow its advance.
At its peak, the Tartar Fire was one of the most active and dangerous incidents in the Northwest Geographic Area, drawing national aerial and ground resources. The fire burned at 0% to 11% containment for its first week before crews began making meaningful progress along the southern and eastern flanks.
Suppression Progress
According to the most recent situation report, firefighters have secured the fire line north of the Mann Creek containment line and are working to ensure those sections are cold — meaning no residual heat that could reignite. Crews are shifting focus to the western side of the fire, where some sections remain active.
At 87% containment, the Tartar Fire is expected to reach full containment within the coming days barring significant weather changes. Fire managers say the primary remaining risks are spotting from wind events across partially completed lines and smoldering material in the interior.
Agricultural and Infrastructure Impact
The Tartar Fire caused significant damage to ranch infrastructure, fencing, and hay reserves across Washington County. The agricultural community in the Weiser area has been mobilizing mutual aid to assist affected operations. USDA Farm Service Agency offices are available to assist eligible producers with emergency livestock assistance and other agricultural disaster programs.
Evacuation Status
Most evacuation orders associated with the Tartar Fire have been lifted as containment has improved. Residents previously under evacuation should check with Washington County Emergency Management before returning to ensure their specific properties are cleared for re-entry. Some road closures may remain in place to support ongoing mop-up operations.