  Unconfined granular flows along an inclined plane are investigated
experimentally. During a long transient, the flow gets confined by quasistatic
banks but still spreads laterally towards a well-defined asymptotic state
following a nontrivial process. Far enough from the banks a scaling for the
depth averaged velocity is obtained, which extends the one obtained for
homogeneous steady flows. Close to jamming it exhibits a crossover towards a
nonlocal rheology. We show that the levees, commonly observed along the sides
of the deposit upon interruption of the flow, disappear for long flow
durations. We demonstrate that the morphology of the deposit builds up during
the flow, in the form of an underlying static layer, which can be deduced from
surface velocity profiles, by imposing the same flow rule everywhere in the
flow.
