  Two-particle correlations in relative rapidity and azimuth are studied for
the p-Pb collisions at the LHC energy of 5.02 TeV in the framework of
event-by-event 3+1-dimensional viscous hydrodynamics. It is found that for the
highest-multiplicity events the observed ridge structures appear in a natural
way, suggesting that collective flow may be an important element in the
evolution of the system. We also discuss the role of the charge balancing and
the transverse-momentum conservation.
