The Valley Fire started on September 12 and exploded to 40,000 acres by the morning on September 13. Several residents in Middletown say they also have no running water.

Hundreds of refugees have sought shelter at an evacuation center at the Napa County Fairgrounds in Calistoga, which was already crowded by attendees at a weekend bike rally in the area.

Mike Lopez, the president of CAL FIRE, talked to Good Morning America on Sunday and was asked whether exhaustion was a factor amid a long exhausting season for firefighters.

Further to the east, firefighters worked to beat back the Butte Fire raging in Calaveras and Amadaor, outside Sacramento.

More than 5,000 residences are without power, the fire department said, and an unconfirmed number of structures have been destroyed.

Four fighters were injured Saturday.

The so-called Valley Fire, now ranking as the most destructive among scores of blazes that have raged across the drought-stricken Western United States this summer, came amid what California fire officials described as “unheard of fire behavior” this season.

Separately, authorities ordered the entire community of San Andreas of more than 2,700 people to evacuate on Friday, but lifted the order when flames headed away from town.

A school, blocks of homes, an apartment building and businesses were all destroyed in Middletown, home to some 1,300 people, according to media.

Four firefighters suffered second-degree burns and were taken to UC Davis Medical where they were in stable condition.

“This fire has burned much quicker than we’re able to get resources into the area”, Berlant said.

The fire eventually moved on and Donpineo drove through falling ash to Kelseyville, where he was waiting for word about his friend’s house in Hidden Valley, and about Harbin Hot Springs retreat, where he lives. By Sunday afternoon, firefighters and crew had managed to increase containment of the fire to 20 percent. Away from the burned-out cars and smouldering remains of homes, Annette Stout and other residents who fled rested at evacuation centres.

The cause of both massive fires -which have scorched more than 164 square miles -remains under investigation. There are dozens of Sequoia groves in the Sierra Nevada, and some trees are 3,000 years old.