The Tartar Fire near Weiser in southwest Idaho — one of the most destructive single fires of the 2026 Pacific Northwest fire season — has reached 87 to 89 percent containment after burning 158,027 acres in Washington County. Mop-up operations are ongoing as firefighters increase depth around the fire line, but Idaho continues to battle six large fires overall, contributing to one of the most active fire seasons on record for the state.

Tartar Fire: From Runaway Blaze to Near Containment

The Tartar Fire ignited on July 24 in Washington County, Idaho, from an undetermined cause. Within days it had grown explosively, burning through tall grass, brush, and timber in terrain along the Weiser River drainage. On approximately August 1 and 2, the fire ran 20 miles toward the city of Weiser, impacting structures along US Route 95 and triggering mandatory evacuations for communities in its path.

At its peak, the fire had grown to over 138,000 acres with containment at just 13 percent. Firefighters faced extraordinarily difficult conditions — extreme heat, low humidity, and gusty winds — before a combination of tactical suppression work and somewhat more moderate conditions allowed crews to make significant containment progress in subsequent days.

By August 4, containment had climbed to 41 percent at 138,271 acres. By August 10, it had reached 87 percent at 158,027 acres. The most recent InciWeb update from August 11 reported that firefighters were increasing mop-up depth around the fire line and making progress securing the northern edge, with 459 personnel still assigned to the incident.

Combined Idaho and Oregon Border Fire Impacts

The Tartar Fire burned in close proximity to other fires straddling the Idaho-Oregon border. At one point, the combined Tartar Fire, Fox Fire, and related incidents burning on either side of the state line had collectively charred more than 238,960 acres. The Fox Fire reached 46 percent containment concurrently with the Tartar Fire's growth phase.

Idaho's Broader Fire Picture

Even with the Tartar Fire nearing containment, Idaho still has six large fires listed in the NIFC daily report as of August 15. The Boise State Public Radio earlier reported that the latest wildfire potential forecast shows all of Idaho at above-average risk for significant wildfire activity through September, meaning the state's fire season is far from over.

Idaho wildfire managers have been relying heavily on mutual aid resources throughout the season, with the state drawing on crews and equipment from across the Western United States to manage simultaneous incidents under sustained extreme fire weather conditions.

Weiser Area: Road to Recovery

For communities near Weiser and along US-95 in Washington County that were evacuated during the height of the Tartar Fire, the focus is shifting to damage assessment and recovery. Hay fields and rangeland that burned during the fire's explosive run represent significant agricultural losses for an area where ranching and farming are central to the local economy.

Capital Press reported on August 11 that hay burns from the Tartar Fire near Weiser were among the most visible and economically significant losses of the fire. Local agricultural extension offices and USDA Farm Service Agency representatives are expected to conduct assessments to help affected landowners access disaster assistance programs.