Trying to add a payment method? You can do this on the 
QuickTake:
The Emigrant Fire, now the largest in Lane County this year, has scorched about 6,000 acres. Watch a time lapse of the pyrocumulus cloud it formed over the Willamette National Forest.
This story has been updated to include the latest acreage estimate Wednesday and scientific perspectives gathered Tuesday.
In the shadow of Diamond Peak, the lightning-caused Emigrant Fire has burned so intensely and rapidly that it has formed its own weather and clouds.
Smoke billowed over the Willamette National Forest from sunrise to sunset Monday. Underneath it, the fire grew — 7,400 acres by Wednesday —according to the National Interagency Fire Center.
Crews with the U.S. Forest Service and Oregon Department of Forestry are working around the clock to slow the Emigrant Fire. It has raged across ridgelines and toward Hills Creek Reservoir, about 20 miles southeast of Oakridge.
Helicopters and planes have circled the forest since Sunday night, when the fire first sparked and grew initially to about 300 acres, quadrupling over the first night to nearly 1,200 acres. On the ground, firefighters searched for places to hold their lines. They found traces of a battle nearly 15 years ago against another massive fire.
Reburning in old scars
The Emigrant Fire is burning in the same steep terrain, where the 2009 Tumblebug Complex spread under similar windy and dry conditions. It consumed 14,570 acres.
An assessment from the Middle Fork Ranger District at that time concluded that the fire may have killed seeds in the cones as the fire blazed through the tree tops, limiting natural regeneration. What was left behind were dead and downed trees in an open landscape, where the Emigrant Fire is now burning.
Wildfire risk scientists like Oregon State University’s Chris Dunn call this reburn, a cycle that historically occurred every 20 to 25 years. Dunn pointed to research that suggests natural fire regimes once kept these burns in check, but decades of suppression and logging have disrupted fire-adapted forests, reshaping their ecology in a changing climate.
Credit: Ashli Blow / Lookout Eugene-Springfield
Such studies aim to guide land managers on how to handle burn scars and what remains within them. But ultimately, the decision comes down to communities and their governments.
“So there’s this trade-off, you know, of maintaining the ecosystem integrity and the ecological conditions that we love as Oregonians,” Dunn said, also broaching other options like salvaging down timber and road maintenance. “And all that just fits into a bigger picture of proactive land management.”
Pyrocumulus clouds becoming more common
In the land where the Emigrant Fire now burns, managers left ghostlike trees — both standing and fallen — on the landscape.
This year, after weeks of drought, these snags dried like tinder and ignited when thunderstorms brought lightning strikes across Lane County on Monday. The fire became intense and explosive nearly upon ignition.
Its heat eventually created rising air currents Monday that eventually produced a pyrocumulus cloud — a towering formation that forms when extreme heat combines with moisture and unstable air.
“Pyrocumulus used to be very rare in the Western U.S., and especially Oregon, but are becoming more common as wildfires are becoming more intense during the last 10 to 20 years,” said Oregon state climatologist Larry O’Neill.
“Even though the wildfire season has been relatively tame this summer, the underlying conditions for explosive wildfire growth are present, which this fire demonstrates,” he said.
The cloud dissipated Tuesday, though gusts from the unstable atmosphere fanned the flames. The fire is likely to burn for days to come.
