  We study the average properties of the gluon cascade generated by an
energetic parton propagating through a quark-gluon plasma. We focus on the
soft, medium-induced emissions which control the energy transport at large
angles with respect to the leading parton. We show that the effect of multiple
branchings is important. In contrast with what happens in a usual QCD cascade
in vacuum, medium-induced branchings are quasidemocratic, with offspring gluons
carrying sizable fractions of the energy of their parent gluon. This results in
an efficient mechanism for the transport of energy toward the medium, which is
akin to wave turbulence with a scaling spectrum $\sim 1/\sqrt{\omega}$. We
argue that the turbulent flow may be responsible for the excess energy carried
by very soft quanta, as revealed by the analysis of the dijet asymmetry
observed in Pb-Pb collisions at the LHC.
