First off, I'm not a big fan of social media.
I also maintain that the best plan for an emergency or disaster is to plan. Be prepared. Get trained. In a variety of areas.
However, I am willing to admit that it is heartening and gratifying to see that ordinary people, with the tools at their disposal, can do extraordinary things in the face of major disasters.
(And, even though I personally hate it, I'm willing to concede that even Slack has its uses ...)
Randall Monroe predicted the nature of social media speed in spreading disaster news:
Then he discussed it in 2011 when the east coast USA earthquake proved him right:
https://blog.xkcd.com/2011/08/24/earthquakes/
We may hate some aspects of various social media, but they can work to benefit the community.