Nearly a month after flames broke out deep in the Mt. Hood National Forest and eventually swept across more than 12,600 acres, the Austin Fire entered Sunday under dramatically quieter weather conditions, but with hundreds of firefighters still on the ground and a continuing investigation into the human activity that started the blaze.
The fire was holding near 12,610 acres Sept. 6 after rainfall, cooler temperatures and higher humidity interrupted weeks of expansion through the upper Clackamas River drainage southeast of Estacada. Containment has remained near 20 percent in the latest reporting, while crews continue securing a perimeter that proved difficult to establish during the fire’s rapid growth in August.
Investigators have now determined that the Austin Fire was human-caused, adding a new dimension to an incident that has consumed thousands of acres of federal forestland, closed roads and recreation areas and forced evacuations along portions of the Clackamas River corridor.
Exactly what happened on Aug. 9 remains under investigation.
Authorities have not identified the activity responsible for the ignition, nor have they announced that a suspect or other responsible party has been identified. No public finding has attributed the fire to a campfire, vehicle, equipment, electrical system, fireworks, arson or another specific source. Investigators have also not said whether the act that started the fire was accidental or intentional.
The fire began Aug. 9 on the Clackamas River Ranger District of the Mt. Hood National Forest, approximately 25 miles southeast of Estacada in Clackamas County. The origin placed firefighters in rugged forest country where steep terrain, heavy timber and dry vegetation would soon become central obstacles to containing the flames.
By Aug. 19, the Austin Fire had grown to approximately 2,900 acres. Three days later it was approaching 4,500 acres. The perimeter expanded beyond 5,600 acres by Aug. 25 and then accelerated sharply, reaching approximately 8,781 acres by Aug. 27.
The fire crossed 10,000 acres by Aug. 29.
Two days later, approximately 10,708 acres had burned. By Sept. 1, the footprint had climbed to approximately 11,682 acres as firefighters continued confronting active fire in timber and heavy ground fuels. The eventual mapping of approximately 12,610 acres marked a fourfold increase from the fire’s size less than three weeks earlier.
Much of that expansion occurred while containment remained at or near zero. Firefighters could not simply surround the blaze with a continuous line through every portion of the rugged landscape. Suppression operations instead relied on forest roads, accessible terrain, heavy equipment and carefully selected locations where crews could establish lines without placing firefighters in unacceptable danger.
The arrival of widespread precipitation changed that battlefield.
Rain moved across the Mt. Hood National Forest during the first days of September, soaking vegetation and raising humidity across an area that had spent much of August supporting active wildfire growth. Flames that had advanced through dry forest fuels were reduced largely to creeping and smoldering activity as moisture reached the fire.
That change has allowed crews to move aggressively into work that was considerably more difficult during the fire’s expansion. Firefighters are reinforcing existing lines, locating pockets of heat, removing combustible vegetation and extending contingency lines designed to hold if the forest begins drying again.
Approximately 655 firefighters and support personnel have recently been assigned to the Austin Fire, maintaining one of the larger suppression operations underway in Oregon. Crews have continued working around the perimeter while heavy equipment is being used where terrain permits to clear vegetation and strengthen defensive lines.
The rain has bought time. It has not ended the fire.
Heavy logs, stumps, root systems and accumulated forest material can retain heat long after rainfall suppresses visible flames. Those fuels can continue burning beneath the surface and become active again when temperatures rise, humidity falls and vegetation dries. Fire managers are therefore using the current weather window to secure as much of the perimeter as possible rather than treating the rainfall as the conclusion of suppression operations.
Restrictions around the fire underscore that continuing threat.
Level 3 evacuation orders have remained in effect in portions of the upper Clackamas River corridor under the latest reporting, while Highway 224 has remained closed to public travel east of Fish Creek. Forest roads, trails and recreation areas within the affected region have also been subject to closures as firefighting equipment and personnel continue moving throughout the incident area.
Some recreation access has begun returning outside the immediate fire zone. Timothy Lake recreation areas have reopened with access from the north, although restrictions remain elsewhere in the forest and fire-prevention rules continue to apply.
The Austin Fire has so far avoided the structural destruction associated with some of Oregon’s most damaging wildfires. No structure losses or firefighter or civilian injuries were identified in the latest incident reporting. Structure-protection preparations have nevertheless remained part of the response as crews defend developed areas and monitor changing conditions along the fire’s perimeter.
The confirmation of a human cause now leaves investigators with another task unfolding behind the suppression lines.
A human-caused wildfire classification encompasses a broad range of possible ignition sources and does not by itself establish criminal conduct. Investigators must determine the specific origin and circumstances before responsibility can be assigned. No agency has publicly announced criminal charges or accused anyone of deliberately starting the Austin Fire.
Whatever investigators ultimately determine, the scale of the resulting fire is already established across the landscape.
From its Aug. 9 ignition, the Austin Fire advanced across approximately 12,610 acres of the Mt. Hood National Forest before September rain interrupted its expansion. The fire forced evacuations, closed transportation and recreation corridors and required a response involving hundreds of firefighters during an already demanding Oregon wildfire season.
Oregon remains far from finished with that season.
Large fires continue burning across the state, and fire officials have cautioned that September precipitation does not eliminate the underlying threat. Forests and grasslands subjected to prolonged summer dryness can lose the benefit of rainfall quickly when warmer temperatures, lower humidity and wind return. Oregon fire seasons routinely extend well into the fall, keeping suppression agencies positioned for additional starts and changes on existing incidents.
For crews southeast of Estacada, the next phase is being fought less against an advancing wall of flame than against the heat left behind.
Firefighters are working through miles of forest perimeter, strengthening lines and finding residual fire before the weather turns against them again. Behind that work, investigators continue reconstructing the beginning of the Austin Fire, seeking the still-undisclosed human action that started Aug. 9 with an ignition in the Mt. Hood National Forest and ended with more than 12,600 acres burned.