Recently, it has been found that the spatiotemporal evolution of auroral emission regions, as depicted by the ultraviolet imager (UVI) onboard the POLAR spacecraft, follows well-defined power law statistical relations characteristic of complex systems near criticality <Uritsky et al., 2002b>. In this study, we continue our investigation of scaling features in the auroral emissions with emphasis on their dynamical characteristics. Based on an analysis of more than 6,700 emission events, we estimate the so-called spreading critical exponents that govern the mean field evolution of localized perturbations in nonequilibrium systems with spatially extended degrees of freedom. We show that the auroral emissions display scale-free spreading behavior that manifests itself through characteristic power-law auroral emission area dynamics. The spreading exponents so obtained are consistent with scaling relations predicted for self-organized criticality.