The proposed ontology (full version) semantically describes concepts and entities relevant to risk assessment, using flooding as case. This includes the semantic definition of the natural hazard itself, i.e., flooding, as well as entities to describe the process of flooding and its intensity, respectively, using e.g. inundation depth, flow velocity etc. Furthermore, the ontology defines various intermediate assessment products and assessment results such as degree of damage, absolute damage, or annual average damage. In doing so, the ontology paves the way for implementing user assistance in risk assessment software tools, auto-generation of metadata, and linking data within the risk assessment domain. More information can be found in Scheuer et al., 2013.