With lipid bilayer-bilayer junctions in mind as model systems for the study of cell-cell junctions, we have examined adhesion between simple lipid membranes using fluorescence resonance energy transfer (FRET) and fluorescence interference contrast microscopy (FLIC) to map the interfacial topography. The contact can take the form of uniform adhesion, with an intermembrane separation of nanometers, or nonuniform adhesion, in which blisters hundreds of nanometers in height coexist with tight adhesion zones. We find that blisters can result as a consequence of rapid interbilayer contact induced by osmotic shock. We develop a model for the formation and stabilization of the blisters, confirming that these phenomena are governed mainly by hydrodynamic flow in the intermembrane space.