Firefighters hope shifting winds and cooling temperatures will aid efforts to battle a wildfire in a forest in far northern California that has displaced thousands and burned at least 100 structures. Authorities have arrested a 30-year-old woman on suspicion of starting the Fawn fire in the Mountain Gate area north of the city of Redding. The blaze covered more than 10 sq miles (26 sq km) and was 10% contained on Friday night, according to the California Department of Forestry and Fire Protection, or Cal Fire. Nearly 2,000 residents were under mandatory evacuation orders and another 7,400 were under evacuation warnings, according to the California highway patrol. Cal Fire said 9,000 structures were threatened. Photos and video showed some homes blazing but the number of residences lost was not known. Damage assessment teams went out on Saturday. The fire erupted at 4.45pm on Wednesday and grew explosively in hot and gusty weather in the region about 200 miles north of San Francisco. North-north-east winds were expected to shift to become south-south-west and be in firefighters’ favor, Cal Fire said on Friday. However, firefighters will likely encounter steep terrain during their efforts to control the blaze in the coming days. Temperatures in the 80sF (27C) are likely to slowly drop into the 70sF over the next several days, officials said. Alexandra Souverneva, 30, of Palo Alto was under arrest on suspicion of starting the fire, Cal Fire said. Workers at a quarry reported seeing a woman acting strangely and trespassing on Wednesday. Cal Fire said Souverneva later walked out of brush near the fire line, approached firefighters and said she was dehydrated and needed help. Officers came to believe Souverneva was responsible for setting the fire, officials said. She was booked into the Shasta county jail. It wasn’t immediately known if she has an attorney. Souverneva, who had a lighter in her pocket, was charged with felony arson to wildland with an enhancement due to the declared state of emergency California is under, said the Shasta county district attorney, Stephanie Bridgett. Souverneva was being investigated for starting other fires in Shasta county and throughout the state, Bridgett said. The Fawn fire is the latest destructive fire to send Californians fleeing this year. Fires have burned more than 3,600 sq miles in 2021, destroying more than 3,200 homes, commercial properties and other structures. Those fires include two big forest blazes growing in the heart of California’s giant sequoia country on the western slope of the Sierra Nevada. Smoke from those fires raised air quality concerns in the San Joaquin Valley below the Sierra and also darkened skies over greater Los Angeles on Thursday. Air regulators issued a smoke advisory but said the heaviest smoke would remain in the upper atmosphere and impacts on surface air quality would be in local mountain ranges. Historic drought tied to climate change is making wildfires harder to fight. It has killed millions of trees in California alone. Scientists say climate change has made the West much warmer and drier in the past 30 years and will continue to make weather more extreme and wildfires more frequent and destructive.