The videos show the propagation of heavier Newtonian fluid fronts (displacing fluid) and lighter polymer fronts (displaced fluid) in a lock exchange release flow in inclined pipe at 7deg. As the partition is opened, a gravity current is generated which causes the heavier fluid to slump to the bottom of the pipe and propagates downstream while a counter-flow of the lighter non-Newtonian polymer fronts (concentrations: 0.00 wt.%, 0.20 wt.% and 0.30 wt.%) will flow upstream at the top of the inclined pipe (pipe ID= 0.04m, length of pipe= 1.20m).