Recent measurements at the shelfbreak in the western Arctic have demonstrated the importance of boundary current processes in driving the exchange of water between the shelf and open basin. Such exchange is vital in ventilating the cold halocline, yet the precise mechanisms by which this happens have been difficult to pin down. This is in part due to the small horizontal scales of motion that characterize the Arctic Ocean. The existence of a strong, narrow shelfbreak current in the Chukchi and Beaufort Seas has now been established. The jet varies seasonally and interannually, but it is the mesoscale variability that is most important for the cross-slope flux of water. Several mechanisms are likely at work, including baroclinic instability---which leads to eddy formation---and wind-forced exchange. A high-resolution moored array has offered a unique view of these processes, giving us the opportunity to diagnose the relevant dynamics and to quantify the impact of the exchange. At the same time, this high-resolution glimpse has uncovered new questions.