Ice flow speed within an ice sheet can vary from a few meters to thousands of meters per year. Fast flowing ice streams can affect sea level, and their flow variation is one factor that determines whether an ice sheet is gaining or losing mass. But different ice streams exhibit different behaviors, and these spatial and temporal variations are not well understood, causing uncertainty about sea level change when ice streams stop or accelerate. Bougamont et al. used a three‐dimensional ice sheet model coupled with a model of the underlying subglacial environment to investigate the relationship between ice flow and basal till properties. This new coupled model reveals new and significant complexities in ice stream behavior, which are related to the spatial and temporal evolution of bed properties. Furthermore, they found that even small differences in the subglacial hydrology can significantly influence ice stream flow. Their results also reveal that ice streams may well have a memory insofar as their current flow is conditioned by their previous behavioral history and physical condition. The study is a step toward understanding the complex behavior of Antarctic ice streams. (Journal of Geophysical Research‐Earth Surface, doi:10.1029/2011JF002025, 2011)