It was an unexpected lifeline during Hurricane Harvey, and it’s still being used to help victims.

Nextdoor says they received tens of thousands of new Houston users during Hurricane Harvey alone. They had a more than 500 percent increase in posts, replies and alerts. More than 3,000 urgent alerts were sent out a day. Normally, that number is about a dozen.

“You never get used to it. Believe me," Kris Moore said.

It’s not the first, but the fourth time Kris Moore’s home has flooded from a storm.

“Every flood I've been through has been totally different," Moore said.

She’s been through Allison, Tax Day and Memorial Day floods. Now Harvey has also stopped by.

But Moore says there’s something different about this time around.

“It was comforting more than anything, I think," Moore said.

She was connected like never before to her neighbors through the Nextdoor app.

“It was also a lifeline to see what was going on in the immediate vicinity. Because on the news, the TV was on, you could watch the news, you could see what was going on in the city or the world, but not was was going on in the immediate vicinity," Moore said.

It works much like any social media, but the app is specifically designed for neighborhoods to communicate, and for some during Harvey, that meant that difference between life and death.

“Just to know things are happening in the neighborhood, and you’d be helped eventually," Moore said.

Kristin Kim says she uses the app now for advice.

“Knowing where to go. Should I be finding a contractor?" Kim said.

But it’s not just the app. It’s Facebook, too. Groups have been formed to just to offer that same advice, help or even just support.

“'Cause we’ve never been through this so we don’t know what to expect. Sometimes others may have an answer that we don’t know yet," Kim said.