The ability to dynamically change data input to a computation is a key feature enabling simulation to be used in many applications. In this study, computation of geophysical mass flow is updated on the fly by changing terrain data. Accommodating such changes in a parallel environment entails new developments in parallel data management and gridding. Adaptivity, and in particular unrefinement, is critical for maintaining parallel efficiency. The application under study in this work is the result of a multidisciplinary collaboration between engineers, mathematicians, geologists, and hazard assessment personnel. In addition, adaptive gridding enables efficient use of computational resources, allowing for run-time determination of optimal computing resources. Combining these attributes allows run time conditions to inform calculations, which in turn provide up-to-date information to hazard management personnel.