Some social media sites are getting downright ancient. I think Twitter celebrated its 10-year anniversary in 2016. While some have been later to the game like Google +, which has not been that successful, others like Snapchat have found an audience.
In the case of Snapchat it has primarily been a younger crowd who has picked up on using this tool. See Can Snapchat Help Government Engage a Younger Audience? Some of you may be thinking, "The younger crowd is not interested in disasters and preparedness." Which I'd have to agree with — until there is an event that has everyone's attention. The first place they will turn to is their friends on the social media channels that they routinely use, e.g., Snapchat.
I think one way to think about the proliferation of new social media sites is that they are like foreign languages, in that we never used to have to pay attention to them, but in today's world there is no one monolithic culture, language or social media tool that reaches everyone. Our approaches to communicating need to change with the times.
Note that in the article BeReadyUtah was mentioned as an agency already using the Snapchat platform. Check them out!