The fire broke out Wednesday and the heavy brush and trees in the area have caused it to rapidly spread and expand.
More than 1,985 firefighters were working to protect buildings and homes in the area. The blaze is burning away from communities, but 500 structures were threatened. The blaze is burning in the Barton Flats area south of Big Bear near Highway 38.
On Sunday, all firefighters received a letter in honor of Father's Day.
Highway 38 was closed from the east side of Angelus Oaks to Lake Williams.
A smoke advisory was issued for Morongo and Coachella Valleys. The smoke from the fire could be seen for miles. Campgrounds were evacuated in Barton Flats, Seven Oaks, Heart Bar and the South Fork Area.
All hiking trails in the San Gorgonio Wilderness Area were closed. Pacific Crest Trail were closed from Whitewater Preserve to Onyx Peak.
The cause of the fire remains under investigation.