The dynamic behaviour of the L-H transition in ASDEX Upgrade is described. We focus on two dynamic phenomena: Dithering Cycles and ELMs. The Dithering Cycles are characterized experimentally; then, a theoretical model is presented which explains the cycle as a limit cycle oscillation at the transition. With regard to ELMs, the modulation of heat and particle fluxes into the divertor due to ELMs is studied, quantitative results from thermography of the target plates are given.