As deadly fires force tens of thousands to evacuate in California, we look back on those who've lost their homes and businesses

• Lightning and a scorching heat wave are causing hundreds of fires in California, forcing tens of thousands of residents to evacuate.
• Devastating fires are nothing new in California, although their severity has increased in recent years.
• Business Insider Weekly visited Sonoma County residents whose homes and businesses fell victim to an especially brutal wildfire season earlier this year, and their stories are worth revisiting almost a year later.

A scorching heat wave in California is causing hundreds of deadly fires that are causing tens of thousands of residents to evacuate.

The lightning-fueled blazes have already killed five people and injured 33 more, authorities said on Friday.

While devastating blazes are nothing new in California, climate change has increased their severity in recent years. Business Insider Weekly visited residents in Sonoma County whose homes and businesses fell victim to an especially brutal wildfire season in December and January, and one year later, their stories are worth revisiting.

Chris Arai is the owner of the last home standing on a ridge that was swallowed up by the Kincade Fire, the 2019 season's most destructive blaze.

Its survival is possibly thanks to the handmade fire defenses Arai has installed over the past several years.

Arai, an electrical engineer, had dedicated himself to building a home that could withstand wildfires. His painstaking fire-prevention techniques include a concrete basement he poured by hand, a fire-repellent gel he coats his windows with, and a sprinkler system that dampens surrounding vegetation to prevent fires from consuming them.

Fifteen years later, as the Kincade Fire loomed, the local sheriff and multiple fire crews visited his property, and all advised him to evacuate immediately. He said he estimated he had a "95-plus"-percent chance of survival, but evacuated anyway.

And amazingly, his defenses worked, and his house stood standing.

"I would definitely ride it out now. Absolutely. Because now I know that the house didn't burn."

But that doesn't mean Arai is out of the woods. He is one of over 350,000 California homeowners who have been dropped by insurance companies in the past two years, in what some experts have called a crisis.

A similar fate awaited Michelle Hall, whose home 10 miles down the road was completely burned to the ground.

"So the companies, a lot of them wouldn't even, like you said, touch our house," Hall said. "They said absolutely not. We're not going to insure you. It's too high risk."

"I don't want to look at anything that's going to remind me of this ever again. I just want it to be over with and be able to move on."

A local charity is helping Hall's family pay for accommodation while they figure out what's next. Although Hall's family has lived in the house for generations, the fire may finally cause them to say goodbye — Hall is staying in Texas, and plans to move to Idaho while she waits on money from her fire settlement.

"The fires, you know, they're helping push me, and the high costs of living, you know?" she said. "That's probably the No. 1 reason, because if we wanted to move into town, we couldn't do it."

Another local charity, Corazon Healdsburg, set up a "free store" to provide necessities like diapers, socks, and paper towels to people who lost everything.

Moody's estimates the fire cost the average resident $765, and the average business $16,000.

Overall, Sonoma County took about a $725 million hit. The county is preparing to sue PG&E, California's electric utility, for damages. The cause of the fire is still under investigation, but PG&E has told state regulators that it had a problem at a transmission tower near the fire's ignition point.

For one local staple called the Jimtown Store, the losses have been too great to bear. The fires and ensuing blackouts forced it to close in late December. Three years of lost income because of the disasters had become too much to handle for the store that had been open for three decades.

"It's more than a dusty roadside cafe — it really is the heart and soul of this community," co-owner Carrie Brown said.

But even for those who escaped the flames, the future is still uncertain.

Across the state, an insurance crisis is unfolding. Multiple reports suggest that the recent wildfires have wiped out decades of profits for the industry.

In December, as insurers continued to drop policies, the state of California stepped in. It temporarily blocked insurance companies from cutting off close to 1 million more customers in 2020.

Meanwhile, Silicon Valley has offered a technological solution — the startup Zesty.ai uses artificial intelligence to help insurance companies more accurately assess risk.

Zesty's platform rated the iconic Soda Rock Winery as high-risk for fire, even though most other agencies hadn't expected it to burn. Zesty was proven right when the 150-year-old local landmark was leveled in the fire.

David Shew, a former firefighter who consults with Zesty, said the company's model factors in "adjacent structures, what those structures are built out of, how close they are, the vegetation, the age of the structure." He said since the Kincade Fire, residents and businesses have been more sensitive to fire prevention.

Zesty could become an indispensable tool for those who wish to remain in a landscape that will continue to be reshaped by fire.

"The public has to accept the fact that if you choose to live in a fire prone environment, it is a constant piece of work that you have to maintain your structure," Shew said.