how are networks setup in disaster areas?

Hello all. Firstly, I apologize if this is against any rules or if this is not appropriate for this subreddit. If that is the case, please feel free to delete this post. I've been watching the Hurricane Florence news recently and as someone who is currently studying networking, I started wondering how exactly the networks and communications used by the rescue/response personnel are setup in these disaster scenarios. These are situations where there is no power, leasing a circuit from an ISP is not feasible as much of the L1 infrastructure is destroyed or inaccessible, and I imagine satellite connections are difficult with heavy cloud cover. Are they just creating ad-hoc networks? If someone could clarify how networks are setup in situations where there is basically no infrastructure to work with, I would appreciate it. Thanks.