High momentum jets and hadrons can be used as probes for the quark gluon plasma (QGP) formed in nuclear collisions at high energies. We investigate the influence of fluctuations in the fireball on jet quenching observables by comparing propagation of light quarks and gluons through averaged, smooth QGP fireballs with event-by-event jet quenching using realistic inhomogeneous fireballs. We find that the transverse momentum and impact parameter dependence of the nuclear modification factor R AA can be fit well in an event-by-event quenching scenario within experimental errors. However the transport coefficientq extracted from fits to the measured nuclear modification factor R AA in averaged fireballs underestimates the value from event-by-event calculations by up to 50%. On the other hand, after adjustingq to fit R AA in the eventby-event analysis we find residual deviations in the azimuthal asymmetry v 2 and in two-particle correlations, that provide a possible faint signature for a spatial tomography of the fireball. We discuss a correlation function that is a measure for spatial inhomogeneities in a collision and can be constrained from data.