By Lemor Abrams

MIDDLETOWN (CBS13) — A popular app used to help neighbors keep in touch and even find lost pets helped rescue entire neighborhoods from a fast-moving inferno that rapidly devastated a community.

The roaring flames from the Valley Fire somehow spared a tight-knit community.

To understand how, we traveled a few hours south to the heart of San Francisco, to a group of entrepreneurs behind Nextdoor.

“I was ambitious about trying to be part of changing the world,” said Nirav Tolia.

The company’s CEO may help you see the world in a different lens, but we’ll get to his story later.

The startup was put to the test in a small town in Lake County. During the Valley Fire this summer, telephone lines went up in flames. But people still had the web. Here in Middletown where entire communities burned, Nextdoor proved to be a lifesaver.

“Usually it’s for things like a lost cat or a missing dog but this time it was for something really important,” said Annemarie Hosch.

The Valley Fire erupted on a Saturday afternoon and within hours, it was laying waste to neighborhoods with little warning. Hosch knew she had to reach her neighbors fast.

Instead of knocking like she used to do, she posted an urgent message to Nextdoor warning her neighbors to “prepare for evacuation.”

“It was Saturday so most people were in their homes, busy in their yards they had no idea what was going on,” she said. “I spotted the spotter plane.”

Firefighters had enough time to cut fire lines around her community, containing the flames.

“It meant that the firefighters had less people to evacuate when they came here we were already packing up and ready to go,” she said.

While Hosch counts her blessings, millions of others use Nextdoor around the country, posting about local merchants, lost pets, or new neighbors moving in.

Chris DiBeneditto from East Sacramento and his guest from out of town were stranded at home without a car.

“His truck was stolen and everything and he had, nowhere to go…because he’s not from here,” he said. “So my only outlet was this app I had on my phone, Nextdoor.

He got on the app and posted the car’s make, model, color and plate number.

“Two days after the ad was up I had a woman contact me and message was like-‘I’m 99.9 percent’ sure I just found your truck. It ended up being she took a wrong turn down the alley and she saw it,” he said. “It was really powerful to see how a community jumped in. You’re sort of bonding with your community without having to meet them.”

No, you don’t have to meet the neighbor, but in a city with a sea of opportunities where many people prefer to build bridges with complete strangers, Tolia’s network is proving the power of relationships.

“Before, people were discussing things on their porch. Now they’re discussing things on Nextdoor,” he said.

Tolia is the face behind Nextdoor.

“We were creating something we felt we needed in the world. We remembered growing up and knowing our neighborhoods, feeling close to our neighbors,” he said.

His idea didn’t happen overnight, but you could say there was a moment when Tolia and a group of friends thought of something most Californians happen to know a lot about—earthquakes.

“We live in the Bay Area. There are earthquakes and so, we had an earthquake not too long ago and I remember thinking to myself as I woke up at 3 in the morning, that was an earthquake, where am I going to learn more about it?” he said. “Am I going to learn more about it on Facebook? Am I going to learn about it on Twitter?”

And so Nextdoor was born to bring people together even when life literally comes crumbling down.

“I’m most proud of the fact that we’ve created a technology tool that’s used by people across all 50 states,” he said.

The network is only four years old and will go global by next year—a long way from where it started in just 175 neighborhoods. In Sacramento alone, there are more than 2,000 neighborhoods.