Both areas remained under a "red flag warning" issued by the National Weather Service for strong winds, low relative humidity and temperatures topping 32 C, all conditions that can drive the growth of wildfires.
Meanwhile, firefighters battling the deadly and destructive wildfires in the region faced worsening weather conditions.
Several thousand people have been evacuated as the fires swept across the state, although some have been given permission in recent days to return to their homes. Brown has also sought a presidential disaster declaration for the areas around the Mendocino Complex fires.
The evacuation zone included all areas north of Clear Lake, south and east of Bartlett Springs Road at Highway 20, west of Bartlett Springs Road at the Indian Valley Reservoir and south to New Long Valley Road and Highway 20 at Highway 53.
"We feel like we're doing pretty good above Lucerne and Nice, but there is still a lot of potential, and we're using a lot of aircraft to hold (the fire) in place", he continued.
The Ranch Fire was just 22 percent contained, and the River Fire was 50 percent contained. Over 15,000 structures are threatened, while so far, almost 70 residences have been destroyed.
Southeast of Redding, a blaze moved deeper into the Mendocino National Forest, "an area with some hunting cabins and some private property but no towns", Lake County Sheriff Lt. Corey Paulich said. The twirling tower of flame reached speeds of 143 miles per hour, which rivaled some of the most destructive Midwest tornados, National Weather Service meteorologist Duane Dykema said.
A DC-10 air tanker drops fire retardant along the crest of a hill to protect the two bulldozers below that were cutting fire lines at the River Fire (Mendocino Complex) near Lakeport, California, U.S. August 2, 2018.
There are at least 18 major fires burning throughout California, authorities said.
It burned so furiously on July 26 that it created a "fire whirl". In all, they have destroyed hundreds of homes, killed eight people and shut down Yosemite National Park. The whirl uprooted trees and tore roofs from homes, Dykema said.
The National Park Service said Yosemite Valley is not threatened by the fire as of Friday at noon.