Your entire emergency management system must be redundant - after all, it is supposed to be as disaster proof as possible.
If you have one of the emergency management information/incident management software programs, that's great. But what if it fails? Step back to basic word processing and spreadsheets. But what if that fails? Step back to paper-based management. All your forms should be usable at all these levels. All forms used in the software system should be printed and number of copies set aside for manual use. Your training and exercise program should include scenarios where the systems fail and you have to fall back on redundant methods.
Communications systems are another key area for redundancy. Do not rely on one or even two methods of communication. You may have to fall back all the way to runners, people physically running messages by hand. Yes, be concerned about information overload, but if it is a choice of too many or not getting through, go for too many. This can be an issue when members of your emergency response team complain that they get too many of the same messages. Your training must clearly explain the redundancy concept and the need to ensure that the message gets through.
These principles are equally applicable to the general public. Family emergency preparedness teaches concepts such as redundant communications among family members. Another example - while digital copies of important documents are good to have, it can be just as important to squirrel away that paper backup copy.
In the world of real estate, location is everything. In the world of emergency management, redundancy is the same. Ensure that redundancy is a key part of your planning.