Training exercises are an important tool in crisis management, as they can assist in a multitude of tasks, such as planning pre-crisis resource requirements and allocation, response planning and help train emergency personnel for actual crises. To be effective, the exercises have to utilize well constructed scenarios and be able to replicate certain characteristics of a crisis situation. In this paper, we propose a conceptual mathematical modeling approach for the automated generation of scenarios for disaster exercises via certain combinatorial sequence structures. The derived scenarios within an exercise collectively fulfill different notions of combinatorial sequence coverage, thereby providing the means to test existing response strategies for deficiencies as well as to train emergency personnel for their ability to handle different arrangements of events. This guaranteed diversity by construction can be used as a basis to obtain quantitative assurance statements when these scenarios have been successfully mastered by participants in exercises. We illustrate our proposed approach utilizing two different combinatorial structures for two example disasters.