One of the outstanding problems for a next step fusion device is the handling of the power fluxes into the divertor, in particular regarding fast transient heat deposition by Edge Localised Modes (ELMs). For a next step fusion device, such as ITER, Type-I ELMy H-Mode is the reference discharge and therefore of particular interest. At JET a thermography system with high time resolution is able to resolve temperature evolution during and between ELM periods; here, the analysis is focussed so far on Type-I ELMy H-Mode discharges with ELM frequencies of 5-35Hz. Influences from surface layers on the target tiles are investigated in special discharges and taken into account. Results about the distribution of ELM and inter-ELM power deposition on the inner and outer divertor target plates are presented. Additionally, the characteristic ELM power deposition time, the temperature rise time and its dependence on pedestal parameters are studied. The thermal impact due to ELMs for ITER is calculated based on predictions for relative ELM mid plane losses and heat flux evolution on the divertor target pointing on a possible exceed the material limits.