Tweets seem to be a very unsecure channel if you are wanting to send official though apparently non-tranparent [to the general public] info to other public entities.
Tell that to Trump
If you have never worked with state and local EM's during an event like this - then you cannot IMAGINE what the Birmingham office was facing or what they were going through. What likely happened is they "broadcasted on all frequencies" in response to false information.
One of the biggest problems my bosses faced was interfacing with state and local EM. Why? Because 1) They want support and info but 2) They don't want to be told what to do because they want to be left alone. When they are given an "all-clear" by national and state officials - then they hear something else - it causes problems. And rumors fly around ANYWAY - just like war. That was always a problem. But when you have misleading Tweets - that is NOT helpful. There are certain checklists that are followed, CAT's are created ETC. I had to deal with that before but under different circumstances (usually, track changes). The state and local politicians hate it.