In NJ, all state agency emergency/crisis communications are handled through the state OEM and Homeland Security offices. Additionally, we can communicate with our staff through email, text, or phone call. There is no established protocol for communication between the agency and districts. Whenever it has been necessary to reach some or all districts during an emergency, we rely on communications through the district manager's cell phones and email. All districts are required to maintain a website and can notify stakeholder groups through that medium as necessary.

Here is what I got from our emergency management coordinator in response to your question. As you can tell by looking at the document, this is just part of our emergency response manual. I hope this is what you're looking for or at least helps.

"Attached is the Crisis Communications portion of our plan, which may be helpful. It includes a Message Map, which is a useful concept for developing key messages and staying on them. The example is on a livestock disease (and wasn’t developed by MDARD) but is included as part of the process."
5Communications

Thank you, John! That's very helpful.