Forest Restoration Work Likely Caused 2,000-Acre Museum Fire

Sep 12, 2019

Coconino National Forest officials say the Museum Fire that ignited north of Flagstaff in July was likely caused by forest restoration work. KNAU’s Ryan Heinsius reports, the blaze prompted evacuations and threatened several areas of the city.

The smoke plume from the Dry Lake Hills on the Coconino National Forest north of Flagstaff soon after the Museum Fire started on Sun, July 21. Investigators say forest thinning restoration work was likely the cause.
Credit Ryan Heinsius / KNAU

Officials say preliminary results of an investigation show an excavator struck a rock that caused a spark on steep slopes in the forest. The heat remained dormant until hot, dry and windy conditions caused it to grow into a wildfire.

"Rock strikes are common because it’s just part of the terrain. What’s not common is that that kind of heat source holds overnight and reemerges the next morning," says forest spokesperson Brady Smith.

Investigators didn’t find evidence of negligence on the part of the thinning crew. The last piece of equipment in the area was used 14 hours before the first reports of fire, and the operator had completed a one-hour fire watch before leaving.

The work was part of the Flagstaff Watershed Protection Project. Flagstaff voters approved a $10 million bond to fund the work in 2012, and managers say when the Museum Fire started about half of the project had been completed.

The Museum Fire burned nearly 2,000 acres in the Dry Lake Hills. Several homes were evacuated but no structures burned. Some areas of the city still remain under threat from post-fire flooding.