Thomas CopelandBBC Verify
BBC
Satellite images have revealed the scale of two wildfires spreading in southern California.
The Sandy Fire ignited on Monday morning in the city of Simi Valley, north-west of Los Angeles, according to California Governor Gavin Newsom.
Satellite images taken just after noon local time (20:00 BST) on Monday show a large plume of smoke rising into the air just south of the city.
California fire officials said on Tuesday morning that 750 firefighters were being supported by "night-flying water dropping helicopters" to target hotspots.
The Simi Valley Police Department said it had received a report that an individual "hit a rock with a tractor", which sparked the fire, according to the BBC's US news partner CBS.
The fire had since spread across 1,364 acres (550 hectares) and no part of it has been contained, officials said.
Data from Nasa's wildfire monitoring platform shows active hotspots moving further south overnight into Tuesday.
Nasa FIRMS
More than 10,000 homes have been evacuated from Simi Valley and surrounding communities, Newsom said.
A further 3,500 homes are under evacuation warnings, extending into neighbouring Los Angeles county
Los Angeles mayor Karen Bass said officials don't expect the blaze to spread to the city but warnings have been issued "out of an abundance of caution".
The spread of the fire was helped by high winds on Monday morning that eased later in the day, a fire department spokesperson said.
Simi Valley Unified School District officials said classes would be cancelled on all of its campuses on Tuesday.
Around 30 people were killed and more than 10,000 homes were destroyed in fast-spreading fires that broke out in the Los Angeles area in January 2025.
Satellite images also show a fire on Santa Rosa Island off the coast of Los Angeles that has burned 14,600 acres (6,000 hectares) of the Channel Islands National Park, according to the US National Park Service.
The fire was first reported on Friday, but by Monday evening, California fire officials said they had so far not got any part of the fire contained.
At least 70 firefighters and park rangers have been battling the blaze. The US Coast Guard said a 67-year-old man was rescued from the island's shore, according to CBS.
Santa Rosa Island is one of five Channel Islands situated off the southern coast of California. The island is almost uninhabited but experts say it has a unique ecosystem of animal and plant life.
Nasa's satellite-based wildfire monitoring platform shows the fire has moved north-east over the weekend and now appears to be spreading inland.
Graphics by Tom Shiel
