Firefighters continued to battle a fast-moving Southern California wildfire that by Saturday had swallowed up dozens of homes and burned over 20,000 acres.

The Mountain Fire, which erupted Wednesday morning in Ventura County northwest of Los Angeles, quickly exploded in size and jumped a highway toward homes because of strong Santa Ana winds and dry air, forcing more than 10,000 people to evacuate.

Firefighters made some progress on containing the fire in the last day. It was 17% contained and had burned 20,630 acres as of Saturday morning, according to the state wildfire fighting agency Cal Fire. On Friday, containment jumped from 7% to 14% by the end of the day.

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Red flag warnings and “particularly dangerous situation” alerts because of low moisture and high winds earlier this week were no longer in place on Saturday, but forecasters said there would still be elevated fire weather conditions inward from the coast through Sunday. There was a small chance of light rain on Monday, but red flag conditions could return to the area later next week.

An air quality alert was in place across Ventura County through later Saturday because of persistent smoke and ash from the Mountain Fire. The National Weather Service said particulates in the air were at unhealthy levels and could remain unhealthy through the afternoon but noted that conditions could change quickly because of the fire’s behavior or weather. Officials warned people to stay indoors as much as possible and said that anyone who has activity outdoors should wear an N95 mask.

At least 10 people were injured, most from smoke inhalation, but there were no reports of life-threatening injuries or deaths so far, Ventura County Sheriff Jim Fryhoff said.

As crews grappled with low water pressure and power outages that slowed their efforts, images of utter destruction surfaced from the hardest hit area of Camarillo Heights. Homes were burned down to their skeletons and brick chimneys.

“The devastation is absolutely heartbreaking,” Fryhoff said.

Over 130 buildings burned down
Ventura County Fire Department spokesperson Andy VanSciver said crews had counted 132 structures destroyed, most of them single-family homes. Another 88 buildings were damaged as of Thursday’s update.

But the number of damaged and destroyed buildings might go up. VanSciver said firefighters had only surveyed 298 properties, finding three out of four destroyed or damaged.

“This is a slow process because we have to make sure the process is safe,” he said.