The ability of first-responders to communicate with each other and with medical facilities during a catastrophic event is absolutely vital. It is also, though, a challenge with which police and fire departments as well as other emergency response organizations struggle on a regular basis.
There are two main requirements to ensure diverse emergency response personnel and agencies can communicate securely and effectively. The first is the fundamental need for compatible communications equipment. As the armed forces have had to learn the hard way over time (when one branch of the service could not communicate with another because of different types of communications gear), emergency responders must have equipment that is compatible across agency lines. That requires a degree of coordination in the design and procurement of equipment that sounds simple, but has proven difficult in practice. While that situation has improved since the terrorist attacks of September 11, 2001, when serious emphasis began to be placed on disaster preparedness, problems invariably reappear in the midst of a crisis.
The second main requirement to ensure diverse emergency response personnel can communicate with each other involves bandwidth. With the rapid expansion in the number and types of commercial communications systems, especially cell phone networks, space on the electromagnetic spectrum has greatly diminished. This means that emergency responders may not be able to use the airwaves when and how they need. Efforts are made by government agencies, especially by the Departments of Homeland Security and Defense, to protect parts of that spectrum, but the pressure from commercial carriers for every additional bit of bandwidth is strong, and the struggle between the two continues.
Finally, it should be noted that communications gear used by first-responders must be durable; it must be able to survive and function in extremely adverse conditions, including in the midst of a radioactive environment caused by the detonation of a nuclear weapon. This is difficult and expensive requirement, but without it, the communications equipment may not survive the catastrophic event well-enough to function.