The recurring heavy precipitations which have struck the south of France these last few years highlight that the affected cities have little pertinent information on how to manage these emergencies, and therefore appear powerless. In response, the development of a local emergency operations plan (EOP) for communities threatened by natural and technological hazards was made compulsory by French law in 2004. This article describes a systematic risk analysis approach for local EOPs. This method is based on a functional model that represents a local EOP as a set of interacting functions, each of them using resources and controls. This decomposition facilitates the identification of the human, technical, and organizational resources that are essential to safeguard the inhabitants of a community threatened by a hazard. This model provides a precise frame for performing an exhaustive and rigorous risk analysis of a local EOP. Based on this model and this risk analysis, potential failures are identified and organized into fault tree for each function. Then assessment checklists of the functions of the EOP are structured via these fault trees. By using these checklists, the analysis of a local EOP becomes more rigorous, exhaustive, and systematic, which makes it possible to broadly study the criticality of the plan. Therefore, this method enhances the potential success of the pre-planned actions during a disaster. This is the first step of a decision support system for city emergency managers who are designing their local emergency plan.