Stoked by hot, dry winds, the largest of several dozen Western wildfires roared through more drought-parched brush and timber in southern Oregon yesterday, displacing about 2,000 residents after destroying scores of homes, officials said.
An army of nearly 2,200 personnel battling the so-called Bootleg fire, raging in and around the Fremont-Winema National Forest 400km south of Portland, increased their containment lines to 25% of its perimeter, up from 22% the day before, the Oregon Forestry Department reported.
"We are fighting the fire aggressively, and there are active efforts to build a containment line, both direct and indirect, wherever it is safe to do so," agency spokesman Marcus Kauffman said.
But the amount of landscape charred since the blaze erupted on 6 July grew another 40,000 acres yesterday alone to reach an estimated total of almost 340,000 acres, the US Forest Service reported.
Only three other Oregon wildfires over the past century have consumed more acreage, according to state forestry figures.
At last report, the fire had destroyed 67 homes and was threatening 2,460 more.
More than 100 outbuildings and other structures have also been lost.
An estimated 2,100 people were under evacuation orders yesterday and many more were on standby to be ready to flee at a moment's notice.
Extremely incendiary conditions on Sunday forced some firefighting teams to fall back to safety zones for a ninth straight day and regroup as they "looked for opportunities to re-engage," incident commander Joe Hessel wrote in his daily report.
"This fire is a real challenge, and we are looking at sustained battle for the foreseeable future."
The Bootleg stood as the biggest, by far, of 80 major active wildfires that have collectively burned nearly 1.2 million acres in 13 states, according to the National Interagency Fire Center in Boise, Idaho.
More than 19,600 firefighters and support personnel are confronting those flames.
The spate of conflagrations, marking a heavier-than-normal start of the Western wildfire season, has coincided with record-shattering heat that has baked much of the region in recent weeks and is blamed for hundreds of deaths.
Scientists have said the growing frequency and intensity of wildfires are largely attributable to prolonged drought and increasing bouts of excessive heat that are symptomatic of climate change.
Since starting nearly two weeks ago, the Bootleg fire has thrived from a combustible triad of weather conditions - gusty winds, high temperatures and low humidity - that are expected to persist in the days ahead.
Forecasts yesterday added a chance of thunderstorms to the mix.
"Thunderstorms often just come with dry lightning and wind, and don't necessarily produce any precipitation," Mr Kauffman said.
The cause of the Bootleg was under investigation.
