A night shift of firefighters will be added in Salmon La Sac to protect threatened properties as the Three Queens Fire continues to spread east of Snoqualmie Pass.
The size of the fire was estimated at 3,533 acres on Thursday morning.
The fire was approximately 2,923 acres in size Tuesday.
A total of 403 personnel and seven crews have been assigned to fight the wildfire, along with four helicopters and 13 fire engines, officials with Northwest Complex Management Team 13 said Thursday.
The fire was sparked by lightning on July 15.
As of Aug. 15, officials said the fire was at 0% containment.
The wildfire continued to spread along the eastern edge of Kachess Lake on Wednesday, and was moving south and southeast toward Thorp Creek. The fire was expanding through steep terrain, and rolling, burning material was cited as the cause of the growth of the blaze.
Aircraft is being directed to slow the spread of the fire until ground crews can safely begin suppression efforts.
The weather forecast calls for thunderstorms in the area, and officials said the storms may bring gusty winds and lightning, which may start new fires in the area.
