Each episode is broken into several segments: "It Did Happen"-this segment talks about similar disasters happening in other parts of America (or even earlier in the target city featured); "When It Happens/How It Would Happen"-this talks about how the disaster would unfold; and a third segment about how to prepare for the disaster, and interviews with residents in the threatened areas about what they think of the disaster threat. Sometimes there is a segment called "Before It Happens", which shows what is being done to prepare for the disaster.