Live updates: At least 132 structures destroyed by Mountain Fire in Ventura County

Investigators are working hard to determine what sparked the wind-driven Mountain Fire, which quickly scorched more than 20,000 acres in Ventura County.

Firefighters believe the blaze started Wednesday morning in Somis, but they don't yet know the cause.

Brian Williams, who has lived in Somis for 22 years, recalls seeing the smoke pour into the sky that morning after his wife called him.

"Around 9 a.m. she called me and there was smoke coming up over the back of our property pretty fast. I head home and halfway home she said she could see flames, we have a back pasture. It had already encroached onto the house. It was chaos. They had evacuated. The fire was approaching the house."

Investigators are still trying to determine what sparked the Mountain Fire, which spread to more than 20,000 acres and destroyed dozens of homes in Ventura County.

Ventura County Fire Capt. Trevor Johnson says they haven't determined the origin.

"No idea on the cause of the fire," Johnson said. "Again, we are fully committed to bringing resolve to the incident. That is a part of our incident management strategy. But that's under investigation currently."

The Perez family's home was one of several destroyed by flames that tore through a mobile home park in Somis. The family had lived there for more than 25 years and had just moments to grab important documents and escape.

"I don't feel anything now. Everything lost, everything gone, all my memories, all my life was there," Reyna Perez said.

A GoFundMe campaign has been made to help the family.

The Perez family's home of more than two decades was one of several destroyed by flames that tore through a mobile home park in Somis.

At least 132 structures - many of them homes - were destroyed by the Mountain Fire and 88 were damaged, fire officials said in a Thursday evening media update.

Survey teams are still sorting through the damaged neighborhoods, a process that is methodical and slow because they have to make sure gas lines are safe before they enter properties for inspection.

Ventura County Fire Department officials said the survey teams have conducted 298 inspections. The damage numbers are from those inspections, but more properties still have to be examined.

Of the 132 structures destroyed, they didn't specify how many of those were homes - but aerial footage of the fire's path of destruction has shown mostly residential neighborhoods hit hardest by the flames.

Gov. Gavin Newsom declared a state of emergency for Ventura County on Thursday due to the Mountain Fire, which has burned more than 20,400 acres near Moorpark and Camarillo.

"This is a dangerous fire that's spreading quickly and is threatening lives. California has mobilized state resources, including personnel, engines and aircraft from CAL FIRE and Cal OES, to protect communities as our fire and emergency response teams work around the clock to combat this fire," Newsom said in a statement.

The governor's office also got approval on Wednesday for FEMA's Fire Management Assistance Grant, which would split the cost of wildfire response with the federal government paying 75 percent and California paying 25 percent.