Let's focus more on what social media can do for emergency preparation or in case of an emergency.

Advantages over other forms of communication

-- Notification (via your phone). This is a big advantage. To get notification from TV or radio, you have to be watching TV or listening to the radio. Similarly, you have to go to a website to see an update. The weather radio only alerts you to certain types of things. Sirens go off only in urgent situations. With something like Twitter, as you go about your day, you may hear a beep. You pick up the phone and get the latest update about Dorian.

-- A wider range of notifications.

-- Able to include information like images, links, videos, etc.

Disadvantages

-- If the cell network goes down (and they often do in emergencies), you are out of luck. Radio seems the most robust. On the other hand, many emergencies do not knock out the cell tower.

-- Notification depends on the people doing it, and in some cases there is no pressure to get it done right, unlike TV or radio. I subscribed to this notification service provided by the local government. After a year, I realized no one was actually handling it. It was basically a defunct account.

Surely this is not a complete list. Jump in, guys!