How winds from a passing cold front affect the 74,421-acre Grizzly Bear Complex fire over the weekend will determine how fire responders approach digging line to contain and combat it, and whether or not they will lower evacuation levels in the coming days.

Thirty-three structures have been lost to the fire 20 miles southeast of Dayton, Wash. It was sparked Aug. 13 by lighting in the area and is now 10 percent contained.

No changes in the current evacuation levels are planned until after frontal winds test fire lines Friday night and Saturday. Fire officials said they may consider reducing the levels Sunday if containment lines successfully hold the fire. Firefighters battling the inferno are now preparing for a shift in weather from the cold front as they build line, protect structures and respond to spot fires, according to a news release from the U.S. Forest Service.

Firefighters will be on the lookout for virga formation, which occurs when rain evaporates before it hits the ground. Virga often results in strong multi-directional winds which can cause a fire to abruptly change direction, potentially posing a threat to firefighter safety.

To the north, the wildfire continued advancing overnight to Forest Road 300, between Deer Springs and Beaver Springs. Responders scheduled a reconnaissance flight Friday morning to see if the road held the fire before allowing ground forces to enter the area. Structure protection in Slick Ear and Little Turkey is slotted for completion Friday.

Firefighters are to complete preparing structures at Ski Bluewood, including protecting cell and ski lift towers. Crews continue to work the northern flank of the Bear Ridge Fire. The Green Ridge Fire, which started on Aug. 25 north of the main fire, is now under control.

Suppression work on the southeast flank is continuing to be patrolled. According to the news release, all spot fires have been controlled and trees are burned in and around Troy. The Forest Road 4039 containment line needs another 1.5 to two miles of preparation to support a possible burnout operation to prevent the fire from moving southeast again. On the southern side of the fire, Forest Road 62 containment line improvements will continue as needed.

The northeast perimeter of the fire remains a challenge due to inaccessibility of the landscape and the pending wind events.