Sea-ice components of global climate models crudely parameterize processes at the edge of the sea-ice cover, using atmospheric and oceanic drags and ice rheology appropriate to the sea-ice pack rather than the broken edge. This leads to inaccuracies in calculating the location of the sea-ice edge and thus the extent of the cover. We present an analysis of a reduced model of the sea-ice momentum balance in the presence of atmospheric and oceanic jets. We consider the validity of the mixture momentum balance at low ice concentrations using scaling analysis. We present solutions for the ice velocity and ice concentration at the ice edge. Our eventual aim is to parameterize the ice-edge momentum balance so that it can be incorporated easily into the sea-ice component of a climate model.