For the past few weeks, natural disasters have been wreaking havoc around the world and across the U.S. On one (very important) hand, climate change and the role humans play in it is likely making disasters like the recent Atlantic hurricanes worse. But humans are also contributing to disaster recovery and response through, believe it or not, social media and apps. Case in point: the walkie-talkie app Zello was downloaded one million times in one day during the hurricanes, according to BBC, and Techspot reports that the app has gained 6 million new users since last Monday. 

The app works “exactly like a walkie-talkie,” Alex Kantrowitz wrote for Buzzfeed. But it isn’t specifically meant for use as “a hurricane rescue tool,” as the company wrote in a Facebook post about using Zello during a disaster, adding that it’s “only as useful as the people who use it, and as reliable as the data network available.” However, Zello can be used for “real-time, large-group communications,” the Facebook post details, and “unlike texting, it may be more accessible to elderly people or small kids.”

Another example of apps that can be indispensable during disasters is Nextdoor, which its website describes as being used for “neighborhood barbecues” and finding lost cats. But it’s main mission—connecting neighbors—has proven invaluable during the recent hurricanes.

Daniel P. Aldrich, a professor of political science, public policy and urban affairs and director of the security and resilience program at Northeastern University, and Courtney M. Page, a PhD candidate at Northeastern University, wrote about Nextdoor (in collaboration with the company) use by survivors of Hurricane Harvey on The Conversation.

The authors told the story of a family in Houston, Texas, that was stranded on their roof awaiting help following Hurricane Harvey. They weren’t able to reach emergency services like police, FEMA or firefighters, as such resources can “become literally and figuratively swamped during major hurricanes,” the authors wrote. The family used Nextdoor to connect with a neighbor who pulled up via canoe to rescue the family and their pets within an hour. Florida residents have been using Nextdoor to discuss evacuation plans with their neighbors, especially “the elderly and infirm,” according to the authors. It goes beyond the hyper-local level though: nearly “50 agencies have used Nextdoor to share information on preparing for supply shortages, rain, storm surges and high wind,” they added.

Aside from the obvious role technology plays in predicting these kinds of weather events, Nextdoor and Zello are among many platforms and apps that show the new reality of tech being an integral part of disaster response. “Everyone knows that they should have batteries and three days of water and food on hand as extreme weather events roll through,” Aldrich and Page wrote. “But in our view, friends and social media platforms reachable by phone are equally important, because they could be lifesavers.”

Zello and Nextdoor work like hyper-localized versions of platforms like Twitter and Facebook, which have also been used during the recent disasters. Facebook offers the Safety Check feature, which lets users share their status so friends and family can stay updated, while a simple tweet can communicate weather conditions to millions of people. In some instances, this could make help more accessible, as it did following this viral photo of residents of a care facility waist-deep in water during Harvey: after the facility owner’s son posted the photo on Twitter, it was retweeted thousands of time and ultimately led to the residents’ rescue.

But it’s important to note that the U.S. Coast Guard has cautioned against using social media to seek assistance during a disaster, specifically Twitter, as this BBC article reports. The internet is very crowded, to put it mildly, and sussing out who really needs help in an emergency could waste valuable resources that are already stretched thin. (Not to mention that even natural disasters aren’t immune from fake news.) This is where more local apps, like Zello and Nextdoor, play an important role in connecting people with others in their area.

Social ties play a huge role in various aspects of disaster recovery. Aldrich and Page pointed to research done in the aftermath of Hurricane Katrina showing how “tighter connections help vulnerable people get through what can be lethal conditions,” and that, on the slow road to rebuilding, community plays an important role. They cited another study done following a 2014 earthquake in Napa Valley, which showed that people “who are socially active on the ground – volunteering, helping neighbors, giving blood – are similarly active through social media.”

Apps can’t replace standard emergency systems, but they help us connect to an important resource: our neighbors. Historically, neighbors are often the first responders during times of disaster. Writer Rebecca Solnit explained this when she was a guest on Krista Tippett’s podcast On Being last year: “oftentimes, the people who do the really important work in disasters, which doesn’t get talked about much, are the neighbors. Who’s going to rescue you when your building collapses? When the ice storm comes and the power goes out? It’s probably going to be the neighbors.”

It’s a good reminder that, in our digital age, your emergency toolkit now includes what’s on your phone.