  Disorder plays a crucial role in spin dynamics in solids and condensed matter
systems. We demonstrate that for a spin-orbit coupled Bose-Einstein condensate
in a random potential two mechanisms of spin evolution, that can be
characterized as "precessional" and "anomalous", are at work simultaneously.
The precessional mechanism, typical for solids, is due to the condensate
displacement. The unconventional "anomalous" mechanism is due to the
spin-dependent velocity producing the distribution of the condensate spin
polarization. The condensate expansion is accompanied by a random displacement
and fragmentation, where it becomes sparse, as clearly revealed in the spin
dynamics. Thus, different stages of the evolution can be characterized by
looking at the condensate spin.
