A field study designed to examine gap flow south of the Brenner Pass during north foehn episodes, was mounted during August - December 1999, as part of the Mesoscale Alpine Programme SOP. We were interested in examining the potential hydraulic characteristics of gap flow as it leaves the confines of a narrow valley to a widening. In order to assess this we installed a transect of three surface stations measuring wind and pressure precisely, and a Scintec FAS64 Doppler Sodar system. In addition, radiosondes, across-valley temperature transects, and mobile temperature measurements, were able to document foehn events, leading to their explananation. The presentation will show the results of this analysis.