LOS ANGELES (AFP) - The Governor of California declared a state of emergency on Sunday (Sept 13) as raging wildfires spread in the northern part of the drought-ridden US state, forcing thousands to flee the flames.
Twelve blazes are currently burning but two - one about 160km west of the state capital of Sacramento and one about 160km to the 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 26,000ha and was just 20 per cent contained, while the Valley Fire had grown 20,000ha overnight and was zero per cent contained, state fire agency CAL Fire 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 on Sunday (Sept 13) .
The town of Middletown, population 1,300, was particularly devastated by the Valley Fire, according to local daily Santa Rosa Press-Democrat, which said the fire grew from 20ha to 4,000ha 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 1,000 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.
CAL Fire said four of those firefighters suffered second-degree burns while battling the blaze and 5,000 homes were without power.
Throughout Saturday night and Sunday morning, new evacuation orders were issued for nearby communities, including all the way south to the border of the town of Calistoga, at the northern edge of the Napa Valley wine region.
"Thousands of residents have been evacuated from this fire," CAL Fire spokesman Daniel Berlant told AFP. "The Red Cross has opened emergency shelters to provide evacuated residents a place to go."
In a tweet, Mr Berlant said crews had not had a chance to do a full damage assessment on the Valley Fire but "we know 100s of structures have been destroyed".
On the other side of California's Central Valley, the Butte Fire has drawn more than 4,000 firefighters to the Sierra Nevada foothills since Wednesday.
More than 80 homes have been destroyed there and some 6,400 other structures are threatened, Mr Berlant said.
Statewide, nearly 150,000 have been burned in fires under CAL Fire's jurisdiction, almost twice the five-year average, making this possibly the most costly wildfire season on record.
Mr Berlant said that CAL Fire had so far spent more than US$212 million (S$300 million), just since July 1, and that approximately 5,000 firefighters were currently assigned to major wildfires.
The costs of containing other fires, such as those currently burning in Sierra Nevada forests, are largely covered by federal agencies and not included in those figures.
The US Forest Service has spent an additional US$1.31 billion battling fires and says it is approaching its record, from 2002, of US$1.65 billion in firefighting costs.
The state of emergency Mr Brown has declared for the regions affected by the Valley and Butte fires will release additional funds to cover the costs of the firefighting efforts.
National Guard troops have also been called in to aid in those efforts.
The fires have also impacted the state's air quality.
"As a result of the Valley Fire, combined with the drought conditions and other wildfires burning in the state, California's air quality has significantly deteriorated," the Governor said in his emergency declaration.