Cylindrical tanks are widely used to store liquids in industry, where liquefied natural gas (LNG) poses a unique hazard to personnel, assets, and the surrounding community because of its flammability and cryogenic nature. There are regulations, such as National Fire Protection Association standard NFPA 59A, requiring dikes to mitigate the risk in the case of a catastrophic failure of an LNG tank. Dikes help to control pool spreading, limit vaporization, and mitigate the vapor cloud, but these effects would be undermined if the liquids overtopped the dikes. Previous studies of overtopping involved small-scale tests and a medium-scale quadrant setup. In this work, the overtopping study was further enhanced by investigating dike and tank configurations, dike materials, and liquid types through both laboratory-scale and field tests. A CFD model was developed to understand the physics, and the results of CFD simulations were compared with experimental results. The findings of this work can help to provide science-based guidelines for overtopping risk assessment and the design of storage tanks and dikes.