Across the US, coastal communities face increasing threats from flooding, erosion, and rising groundwater tables due to accelerating sea-level rise and changing storm patterns. CoSMoS is a dynamic modeling approach that allows for detailed projections of coastal flooding due to both future sea level rise and storms. … CoSMoS models all the relevant physics of a coastal storm (e.g., tides, waves, and storm surge), which are then scaled down to local flood projections for use in community-level coastal planning and decision-making. Rather than relying on historical storm records, CoSMoS uses wind and pressure from global climate models to project coastal storm impacts under changing climatic conditions during the 21st century. Projections of multiple storm scenarios are provided under a suite of sea-level rise scenarios. These options allow users to manage and meet their own planning horizons and specify degrees of risk tolerance.