TODD VALLEY -- Containment in the Trailhead fire hasn't changed since Thursday, but how much land has burned has. Officials said Friday evening that 2,551 acres are destroyed and fire crews have only contained 12 percent.
Fire crews haven't yet determined the cause of the fire, which started shortly before 2 p.m. Tuesday along the middle fork of the American River near Foresthill.
There's good news for Placer County, the majority of the containment is on that side of the river, but that means bad news for El Dorado County. Some dozers and hand crews even moved from Placer County to El Dorado County because the fire is moving east in that direction.
"Doing structure protection down there they got dozer lines they're doing they're prepping for the fire in case it decides to move up there," said David Janssen with Cal Fire.
An infrared map is created every night so fire crews know their plan of attack.The map shows hot spots, scattered heat and intense heat.
Trudging through steep terrain in this heat isn't easy theres a real potential for dehydration. Cal fire said that's one on their biggest concerns in day four of this fire fight. It's why crews are switched out every 24 hours.
"We kept him longer than that they heat illnesses would be higher," said Janssen.
Just because the fire is worse on the El Dorado County side doesn't mean Placer County is out of the woods. Crews are still working hard to protect the land in case the fire moves up canyons here.
Fire officials say 2,600 structures are threatened.
— CAL FIRE PIO (@CALFIRE_PIO) July 2, 2016