Fire officials were hoping to completely contain the Interchange fire west of Truckee by late Wednesday night.
As of 7 p.m. the fire had burned about 170 acres and was 50 percent contained.
Gene Welch, public fire and safety officer for Truckee Fire, said fire officials were hopeful that the fire would reach 100 percent containment by 10 p.m. Wednesday.
Downed power lines forced the closure of westbound Interstate 80 at about 2 p.m. A tree trimming crew reportedly dropped a limb into a power line, sparking the fire, which burned off westbound Interstate 80 near the Donner Lake interchange.
"The fire has bumped into an old burn, which is helping," Welch said.
Westbound I-80 was closed for about three hours. One lane was reopened to westbound traffic at about 5:30 p.m. allowing traffic over Donner Summit.
Officials for the Truckee Fire Protection District said they were concerned the fire would jump a ridge north of the lake and threaten homes in the Tahoe-Donner neighborhood. No evacuations had been ordered and no homes were considered to be in any immediate danger.
Bryce Keller, Truckee Fire Protection District chief, said a potential evacuation site would be set up at Alder Creek Middle School in case an evacuation became necessary. Residents trying to enter Tahoe Donner were required to present identification in order to keep the roads clear if an evacuation was needed.
As of 6 p.m. more than 300 personnel and 27 fire engines, two bulldozers, four helicopters, six air tankers, and three water tenders to supply engines with water were assigned to the fire, Welch said. Ten more engines en route.
"Collaborating agencies are too many to list," Welch said. "We've got Calfire, Truckee Fire, local law enforcement, Caltrans, the Forest Service, and engines coming from Auburn and Colfax."
Efforts were focused on preventing the blaze from reaching Tahoe Donner, a 6,000 home subdivision.
Calfire's JoAnn Cartoscelli reported Wednesday afternoon that the fire was holding in an area previously burned.
There have been several fires in the Negro Canyon area over the last five decades, including the Donner Fire in 2003 and the Donner Ridge Fire of 1960, which burned from the Donner Lake interchange through what is now Tahoe Donner.