Resonant magnetic perturbation (RMP) experiments at JET with the ITER-Like Wall have shown the formation of pre-ELM footprint structures appearing a few milliseconds before and propagating radially outwards until the major divertor heat load, caused by type-I edge localized modes (ELMs), occurs. The formation of the pre-ELM structures is accompanied by a drop in the electron temperature at the plasma edge. A comparison with a thermoelectric edge currents model results in qualitative agreement to the observations, whereas the dynamics can be understood based on RMP enhanced ballooning modes.