*Modeling and Computing Geophysical Mass Flows.*

**Abstract:** This paper describes one
effort to develop model equations and a computational tool, to facilitate
simulations of geophysical mass flows. We present equations that describe a
``thin layer'' model of flowing granular material. We describe
a computing environment that incorporates topographical data in order to
generate a numerical grid on which a parallel, adaptive mesh Godunov solver
can simulate flow. We discuss several open questions in the mathematics and
modeling of these flows.