PORTLAND, Ore. (KOIN) — As Oregon and Southwest Washington prepare for a historic heatwave, fire crews are still battling down the S-503 Fire on the Warm Springs Reservation.

Officials use aerial infrared technology to get an accurate estimate of acreage burning, which has remained at 6,679 acres — or just over 10 square miles — for several days now. As of 9 a.m. Friday, the blaze was 50% contained.

The S-503 Fire is about 2 miles east of Hwy 26 and 7 miles northeast of Simnasho. The hot, dry conditions and relatively low humidity have been a factor in fighting this fire — but officials say cooler weather in the middle of the week allowed firefighters to make significant progress. However, suppression efforts will be of even higher importance as we head toward record-breaking temperatures this weekend.

With over 300 firefighters, crews successfully established a containment line around the entire fire perimeter by Wednesday evening and its footprint has remained the same over the last few days. Crews were able to maintain a secure perimeter despite a flare-up Thursday night. 

Officials say some resources and teams from the S-503 Fire are now being used to help secure and suppress efforts the Mill Fire which sparked on the Warm Springs Reservation Thursday.  

A burn ban on the Warm Springs Reservation is in effect “until further notice,” according to the U.S. Environmental Protection Agency, and applies to all outdoor and agricultural burning with the exception of ceremonial and traditional fires. The federal agency is also asking reservation residents to reduce other forms of air pollution, including driving and idling vehicles.

Evacuation Levels as of 9 a.m. Friday

  • Level 1 GET SET: All residences west of Kelly Springs Road/Back Walters Road are down to a Level 1 – Get Set evacuation warning. Anything east of Kelly Springs to Reservation Road, including Walters Corners and the community of Pine Grove, is also at Level 1.

The fire first sparked last Friday. It’s not clear what caused this fire to start, officials said. The fire is about 92 miles from Portland.