The 45-mile (72-kilometer) stretch of highway near the state line with OR has been closed since a fire Wednesday turned hills both sides of the roadway into walls of flame.
"They were the largest fires, and as soon as you bought those fires under control, they could re-deploy those firefighters to other areas within the larger area.up to Oregon, Washington and then down to Southern California".
A nearby fire in the Redding area burned some 1,100 homes and killed eight people last month.
Although the fire was not burning near any large towns, Mr Vacarro said about 280 homes were considered threatened.
The latest fire spread to 2,000 acres (809 hectares) by Wednesday evening, forcing the Shasta County Sheriff's Office to evacuate residents along a stretch of Interstate 5 north of the town of Lakehead to the Siskiyou County line, according to the government wildfire tracking website Inciweb.
The two fires destroyed or damaged a combined 8,800 homes and 329 businesses.
Now the state's focus is on two large wildfires in northern California.
Northbound I-5 is now closed at Fawndale Road, north of Redding.
Officials from a number of agencies were meeting Thursday to determine if they can reopen the highway, a key route for commercial trucks, California Highway Patrol Officer Jason Morton said.
The highway runs from the U.S. -Mexico border to Canada. Further north, dozer line along Middle Ridge is serving as a point for additional defensive firing operations in an effort to protect communities along the I-5 corridor, such as Castella and Dunsmuir.
"It isn't a lot of people", he said. Fire officials feared that once the inversion layer sitting over the fire cleared, the blaze would once again explode through the mountainous forest region, heading farther north toward Gibson, east toward Greens Mountain and west toward Damnation Peak.
The fast-moving fire forced truck drivers to abandon their rigs on the highway. At least two trucks were partially melted.
ORIGINAL POST: WEDNESDAY, SEPT. 5, 3:30 p.m. Truckers, firefighters and others aided more drivers.
While New Zealanders fighting fires in OR to the north had been glad of their Swanndris to keep them warm at night, in California the heat was "unrelenting", 30C overnight and 40C during the day. "Whatever occurred here was probably pretty ugly for a while".
It was a ghost road on Friday morning along a 45-mile stretch that has remained closed since a fire two days earlier swept down and turned hills on either side into walls of flame. That's up from than 34 square miles (89 square kilometers) as of Thursday night.