The Thomas Creek fire has jumped in size to 7,279 hectares.
Fire behaviour increased significantly Sunday, particularly in the north and northeast.
This increased fire activity is expected to continue in the coming days as hot, dry and windy conditions will persist, said BC Wildfire.
Smoke has come into Penticton Monday morning after a clear, blue sky weekend.
Without any rain in the forecast, these hot, windy conditions will continue to challenge fire suppression efforts as the fire has moved into the Christie Mountain fire area, said BC Wildfire.
Safety of crews and the public will remain as the top priority, they said.
The Thomas Creek fire, near OK Falls erupted on July 11.
An area restriction order remains in place for the Thomas Creek fire and the over 700 properties on evacuation alert continue.
The 90 military personnel who arrived on the weekend will be working on this fire by Monday afternoon or Tuesday morning, said BC Wildfire.
Today, crews and equipment will continue to work in the Christie Mountain area to create and reinforce guard lines using existing roads, old fire guards and other natural features. This is being done in an effort to get ahead of the fire in the north and northeast sections.
On Sunday, firefighters patrolled the guard line on the west flank and began to demobilize equipment from reinforced guard lines in this area. Fire activity was relatively quiet along this western flank.
Heavy equipment is being used to build contingency guard lines to the east of the fire.