More than 17,000 residents in Southern California were under evacuation orders on Tuesday as a fast-moving wildfire threatened homes in suburban areas.

The Sandy Fire, driven by strong winds, broke out on Monday in the hills above Simi Valley, around 30 miles (48 kilometres) northwest of Los Angeles.

By Tuesday morning, the blaze had burned more than two square miles (about five square kilometres) of dry vegetation and destroyed at least one home, according to the Ventura County Fire Department.

Fire officials said winds initially pushed the flames at speeds of over 30 mph (48 kph), but calmer overnight conditions helped firefighters gain some control.

“We’ve made a lot of progress against this fire with those improved weather conditions,” said Ventura County Fire Department spokesperson Andrew Dowd, adding that crews were trying to contain the blaze before winds pick up again.

The fire was reported to be about 5% contained, and investigators are still working to determine the cause.

Evacuation orders and warnings remained in place across several neighbourhoods in Simi Valley, a city of more than 125,000 people that was covered in thick smoke as firefighting aircraft dropped water and fire retardant.

In a separate incident, firefighters were also battling a much larger wildfire covering about 23 square miles (59 square kilometres) on Santa Rosa Island off the Southern California coast.

That fire destroyed a cabin and an equipment shed and forced 11 National Park Service staff to evacuate. Officials said there was no containment as of Tuesday morning.

Santa Rosa Island, a popular camping and hiking destination, is home to wildlife including island foxes, spotted skunks and elephant seals.