Firefighters are battling a fast-moving blaze in southern California that has swelled over the past day, with authorities warning Thursday is “the period of greatest concern”.

The Hughes fire, about 45 miles (72 km) north of Los Angeles, grew to 10,000 acres (4,000 hectares), forcing tens of thousands of people to evacuate a region already reeling from the most destructive fires in its history.

Forecasters warned that powerful winds were expected to pose further challenge for firefighters, who have so far brought 14% of the fire’s perimeter under control.

The blaze is north of the two ongoing mammoth blazes that have destroyed a number of neighbourhoods in Los Angeles County.

The National Weather Service extended a red-flag warning until Friday morning for most of Los Angeles and Ventura counties as winds push through the area.

“Dangerous fire weather conditions will persist through Friday as fuels remain extremely dry and ready to burn, with Thursday the period of greatest concern,” an advisory said. “Any fire that starts can grow fast and out of control. Have a plan, especially if you are in a high fire risk area.”

More than 31,000 people were evacuated on Wednesday as the fire sent huge flames and plumes of smoke over a hilly terrain in the Castaic Lake area that borders several residential areas and schools.

Local news showed residents near the Hughes fire hosing down their homes and gardens with water and others rushing to evacuate.

Winds in the area were blowing at about 20-30mph (32-48km/h), but could pick up, which would fan the blaze and make it harder for air crews to operate.

Climate change has made the grasses and shrubs that are fuelling the Los Angeles fires more vulnerable to burning, scientists have said.

Rapid “whiplash”-style swings between dry and wet conditions in the region in recent years have created a massive amount of tinder-dry vegetation that is ready to catch fire.

While dry conditions will remain over the next few days, there is some respite on the way for the fire-ravaged region.

Widespread rain is forecast for southwestern California beginning on Saturday afternoon and lasting through to Monday night. Generally, rainfall will total up to half an inch, though the San Gabriel Mountains will fare better with up to 1.5in (4cm).

There is a chance that thunderstorms could also trigger localised heavy rain in some areas across the weekend. A few inches of snow are also possible above 4,000ft (1,200m).

Nearly 500 inmates at a local jail were being evacuated, according to Los Angeles County Sheriff Robert Luna.

Officials said the blaze was different from the Palisades and Eaton fires, which killed at least 28 people and decimated more than 10,000 homes and businesses earlier this month.

Have you been evacuated due to the fires? Get in touch if it is safe to do so.

Two other fires ignited Wednesday further south, near San Diego and Oceanside. The Lilac fire was declared fully contained after burning 85 acres. Like the separate Center fire, which has covered four acres, it burned in populated areas. Evacuation orders have now been mostly lifted.

Dana Dierkes, a spokesperson for the Angeles National Forest, noted the winds and dry brush had made these recent fires much harder to fight.

“We don’t have a fire season in California. We have a fire year,” she said. “We’ve had wildfires in January before, but it’s exacerbated by the Santa Ana winds. The wind is a huge factor when we’ve had such a dry year.”

The anticipated rainfall from Saturday is bringing new fears in the form of mudslides, flooding and landslides. Areas touched by the recent fires are particularly at risk, because torched grounds are less absorbent.

Samantha Granville contributed to this report.