How to Communicate Effectively in a Crisis

I think some of the largest things I've been involved in are natural crises as far as fires go. When you're having to evacuate 20,000, 30,000 people, what does area command look like? What does a field command post look like? How do I conduct evacuations? Who's the incident commander? Communicating is a huge challenge for us. We just don't do it. In the entire nation, I can tell you not teaching across the country. Nobody's handling a hostage problem. So it's something to consider.