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EL DORADO COUNTY — The Trailhead Fire burning in El Dorado and Placer counties grew to 5,444 acres overnight into Monday as it remains just 50 percent contained.

Steep, rugged terrain has proven to be one of the biggest obstacles for the 2,123 firefighters working to extinguish the fire.

 

Fire officials say 2,600 structures are threatened by the flames. So far, no buildings have been burned in the fire.

Evacuations on both the El Dorado County and Placer County sides have been changed from mandatory to voluntary as of 8 p.m. Monday night. Authorities say only residents in the area with ID will be allowed beyond the staffed roadblocks.

For any other evacuation inquiries, you can visit:

The cause of the Trailhead Fire, which began Tuesday, is still under investigation.