The cell phone app Zello allows your phone to act as a two way radio. Available in PC versions as well, Zello allows users to log on to and create 'channels' that other cell phone users can access. Channel owners and moderators can set privileges, invite and block other users. Once the app is installed, a user can monitor any and all channels he or she is connected to.
During hurricanes Harvey and Irma, civilian rescue groups such as the Gray Navy and the Cajun Navy used Zello extensively to take help calls from stranded citizens and in turn would dispatch either their own vessels or any others who might be available and in the area. It's important to note that Zello, like most other cell phone apps, relies on cell tower communication and will not work where cell service has been interrupted.
Pecos Valley Amateur Radio Club Vice President Jim Tucker has created two Zello channels for ham use, though no license is required to operate on a Zello channel. Channel 'PVARC' is primarily for general use among any ham anywhere. 'SENM_SVR_WX' was created primarily as a severe weather net channel for hams or non-ham storm spotters to convey reports. NWS staff and local emergency management staff from around the region are also invited to participate on this channel.