The Bangladesh Delta is at the confluence of the Ganges, Brahmaputra and Meghna Rivers and home to over 158 million people with a high growth rate of ~2.5 million people per year. It is continuously threatened by monsoonal flooding, sea-level rise, saltwater intrusion, sediment load, coastal erosion, land subsidence, blockage of river run-off, and accelerated mountain glacier melt. In the face of such climate variability, residents face tremendous environmental risk related to annual crop/income loss as well as potentially permanent loss of assets and livelihoods. This paper uses a long-running panel survey unique in its efforts to track migrants, both temporary and permanent, over a 25 year period. We link the survey with geodetic and climate data reflecting the various forms of environmental risk that poor rural households must contend with. Regression analysis is used to determine how individual and household migration decisions respond to the various risks, including differences between static risk (i.e., stable over time) and dynamic risk that will continue to evolve rapidly with climate change. We also introduce a variety of control variables to better understand how migration as adaptation may be constrained by factors such as wealth, transportation costs, social networks and demography.