The governor of California has declared a state of emergency as raging wildfires spread in the northern part of the drought-ridden US state, forcing thousands to flee.
Twelve blazes are now burning but two - one about 160 kilometres west of the state capital of Sacramento and one about the same distance east - have been particularly damaging over the last week, destroying hundreds of homes and mobilising thousands of firefighters.
Driven by high winds and soaring temperatures, the Butte fire has burned 26,000 hectares and was just 20 percent contained while the Valley Fire had grown to 16,000ha overnight and was zero percent contained, the state fire agency said.
Governor Edmund Brown "today issued an emergency proclamation for Lake and Napa counties due to the effects of the Valley Fire, which has burned thousands of acres of land and caused the evacuation of residents and damage to highways and other infrastructure," a statement said.
The town of Middletown, population 1300, was particularly devastated by the Valley fire, according to local daily Santa Rosa Press-Democrat, which said the fire grew from 20ha to 4050ha over just five hours on Saturday - before quadrupling in size overnight.
"I'm looking in all directions, and all I see is fire," local fire chief Steve Baxman told the paper.
Nearly 1000 firefighters have been called in to combat the fast-moving blaze, which was tearing through oak-and-grass hillsides dried out from a fourth year of drought.
On the other side of California's Central Valley, the Butte fire has drawn more than 4000 firefighters to the Sierra Nevada foothills since Wednesday.
More than 80 homes have been destroyed there and some 6400 other structures are threatened, Berlant told AFP.