The Valley Fire was reported Oct. 4 east of Boise.

1. Report detail

A down power line likely caused the Valley Fire that continues to burn northeast of Boise, according to a state investigation.

An Idaho Power Co. pole’s wooden crossarm brace broke and an energized line hit the ground, igniting dry brush and grass, according to an Idaho Department of Lands report.

Idaho Power inspected the line three times this year, including the cross arm that appears to have broken, and “no issues were noted in either ground or helicopter inspections,” company spokesman Sven Berg said in a statement.

The cross arm “did not appear to have rot or bug infestation,” according to IDL’s report. “There were no visible outside penetrations other than what appeared to be intended to support the electrical transmission line. There were no indications this item was struck by a large object or projectile.”

Idaho Power “acknowledges the conclusions of the Department of Lands report and remains committed to safely providing reliable, affordable energy to its customers,” Berg said. The company “is grateful for the first responders who worked to quickly contain the Valley Fire and the patience of the customers who were impacted.”

He could not comment further, he told Capital Press.

No structures, vehicles or equipment were damaged, according to the report.

Department of Lands investigators reserve the right to change their conclusion if new information becomes available.

The fire, reported Oct. 4 on the north side of State Highway 21 about a mile east of Boise, had burned 9,904 acres and was 79% contained as of early Oct. 15, department officials said in a release.

The fire was stopped from reaching homes near the Boise foothills largely due to a dozer containment line and hand line built by firefighters. The Robie Creek area remained in Stage 1 (ready) evacuation status.

Equipment and resources have shifted to repairing fire suppression impacts. Seeding and erosion control on containment lines are examples. Some suppression repair was also completed in the fire’s southern area.