McLean says three firefighters and an unknown number of civilians have burns but didn't know the extent.
The fire's growth forced Old Shasta residents to evacuate Thursday morning, Cal Fire said, and the California Highway Patrol warned people in west Redding to be ready to leave as well.
Five residential structures have been destroyed.
One person was killed in a raging, out-of-control wildfire that sent residents racing to flee a northern California city on Friday as flames burned homes and businesses and knocked out power, fire officials said.
Journalists at the Record Searchlight newspaper tweeted about continuing to report on the fire without electricity in their newsroom, and a reporter at KHSL-TV wrote on Twitter that the station's Redding reporters were "running home to gather their things".
It is threatening an estimated 600 homes in the area.
The situation is "very dynamic" and "a heck of a fight", McLean added.
The declarations issued Thursday state that hot temperatures, erratic wind and low humidity have increased the spread of both fires. It is active again Thursday morning and has no doubt grown significantly since Wednesday. It was reported to be just 27 percent contained.
Whiskeytown was once a vibrant and bustling mining town.
Officials emphasized that Yosemite wasn't in imminent danger from the fire.
There have been 3,4000 wildfires in California in the past year, burning 99,000 acres, according to Cal Fire.
The museum in the restored 1861 courthouse is the centerpiece of the park that features remains and relics from Shasta City's days as "Queen City" of Northern California mining. The Cranston Fire is under Unified Command between the USFS San Bernardino National Forest, CAL FIRE/Riverside County Fire Department, Idyllwild Fire Protection District and the Riverside County Sheriffs Office.
In Southern California, thousands remained evacuated as a suspected arson wildfire burned in the San Jacinto Mountains east of Los Angeles. The state previously secured a fire management assistance grant from the Federal Emergency Management Agency to aid containment of the Carr Fire. Thirty to 40 boats caught fire, he said.
The so-called Carr Fire is "taking down everything in its path", said Scott McLean, a CalFire spokesman for the crews battling the blaze. Evacuations are also in place for Apple Canyon Area, Cedar Glen, Camp Scherman Girl Scout Camp, Fern Valley, Hurkey Creek area, Idyllwild, Lake Hemet area, Mountain Center Community and Pine Cove.
Authorities arrested a Temecula man on suspicion of setting the fire.
It wasn't immediately clear whether McGlover had an attorney.
About 100 homes were still under threat in the San Francisco Bay community of Clayton, although firefighters had stopped the progress of a small fire there after one house burned.
Yosemite Valley, the scenic heart of the national park, was closed at noon Wednesday during the height of tourist season as smoke cast a pall on the region from a fire in the Sierra Nevada.