By Sara Puig
Crews battling 23 tenacious wildfires in drought-stricken California have rushed in reinforcements and are preparing for weather that could ignite more blazes.
More than 10,000 firefighters are now tackling blazes that have forced thousands to flee their homes and burned large swathes of land in the most populous US state.
The biggest conflagration, called the Rocky Fire, has drawn in 3200 firefighters.
"Tinder dry conditions from the drought continue to allow wildfires to burn at an explosive rate," said the California Department of Forestry and Fire Protection, or CAL FIRE.
The state is bringing in extra people from southern California to the hard hit north, making already deployed firefighters work overtime and cancelling days off, CAL FIRE spokesman Daniel Berlant told MSNBC.
Resources from out of state, such as the Colorado state air reserve, are also being brought in.
Thunderstorms that can bring lightning, the source of many fires this summer, but virtually no water, are forecast.
And after a cooling of temperatures over the weekend, they are expected to rise again on Wednesday, followed by more thunderstorms on Thursday, CAL FIRE said in a statement.
Many of the 23 fires are actually made up of dozens of smaller lightning fires, Berlant said.
"Right now definitely conditions are dry," he said.
"We are continuing to see the effects of the drought as wildfires can more easily spark and then they're going to spread at these historically fast rates."
The week-old Rocky Fire prompted evacuations as it swept through Colusa, Lake and Yolo counties north of Sacramento, the state's capital, in the north of the state.
More than 13,000 people have been forced to flee homes threatened by Rocky, CAL FIRE says.
Only 12 percent under control, Rocky has burned through more than 26,000 hectares, destroying 50 structures, about half of them homes.
Berlant said late on Monday that the fire ripped through the forests at break-neck speed, with firefighters struggling to keep apace.
"Over the weekend, 20,000 acres (8100 hectares) burned in just about a five-hour period. That's an unprecedented historical rate of spread," he said.
At least 57,500 hectares of land have burned so far, according to figures provided by the state.