Very dry, offshore winds combined with dry forest fuels will combine to elevate fire danger conditions in Oregon to critical levels at the end of the week, say fire weather forecasters with the National Weather Service in Portland.
The most active fire behavior is expected on existing fires or new fires Thursday through Saturday, but officials don't see many new starts related to lightning, with no thunderstorms expected.
High pressure and a thermal heat low are expected to build over the region, causing a rapid rise in temperatures starting Thursday, with highs into the upper 80s by Friday and the low 90s Saturday, the hottest of the three days.
The highest ridgetop winds — with gusts to 30 mph — are forecast to wane by Sunday as the marine layer of clouds rebuilds, dropping temperatures back into the 70s.
Large wildfires that should see increased activity include:
Nearly 1,000 firefighters are battling the fire, which is burning 2 miles east of Oakridge and is 2,297 acres. The fire, sparked by lightning Aug. 12, is 55 percent contained.
Firefighters will take advantage of relatively cool and humid conditions Wednesday and Thursday for burnout operations, setting a backfire about 2 miles long that will check the fire's advance.
About 600 firefighters are on the 3,000-acre fire, which started Aug. 29 and is burning 12 miles southwest of Monument; the cause remains under investigation. Officials say the fire is 62 percent contained with containment expected in the next day or two.
The fire is at 27 percent contained, burning 30 miles northeast of Medford after starting on July 31 by lightning. The fire showed moderate behavior Tuesday, burning through timber in steep, rugged terrain to 2,300 acres. Warm, dry and windy conditions are expected to challenge the 700-plus firefighters on the ground.
-- Stuart Tomlinson