## 5 Discussion  
This study achieved the target of assessing the impact of the wildfires that struck the Attica region in 2021 by combining remote sensing and GIS techniques and free open available datasets. The methods used led to the production of results which helped in understanding the effects of the four examined wildfires. The operational wildfire mapping with the use of Sentinel-2 optical imagery with the application of NBR was effective in mapping the burned areas and assessing their burn severity on a near-real-time basis and with a very good spatial resolution. The later soil erosion risk modeling derived from the RUSLE was sufficient enough to trace the soil loss before and after the wildfire events and understand the risk that each area faces after them. The highlight of this study is the addition of all these products to the web app developed for this purpose thus enabling the getting of an inclusive geospatial intelligence of the post-fire situation. As mentioned above, the wildfires of 2021 constitute one of the greatest disasters Greece has faced. The analysis that has been implemented in this manuscript was related to the wildfires that broke out in the Attica region. Specifically, the study areas consisted of the wildfire incidents that broke out in Varympompmi, Schinos, Vilia, and Lavreotiki. Those regions had been extensively affected by the fires with the burned areas varying from 5 km\({}^{2}\) to 96 km\({}^{2}\). The burn severity demonstrated some very interesting patterns spatially, predominated by moderate-high burn severity values in all regions, except Lavreotiki, where moderate-low severity values presented high frequency as well. Based on the results, the fires affected mostly forestry area consisting of broad-leaved, sclerophyllous, and mixed vegetation. Wildfire incidents usually lead to post-catastrophic events such as the soil erosion phenomenon. In this study, advanced erosion modeling was applied to the above-mentioned regions in Attica in order to estimate the erosion risk resulting from the wildfire incidents. Particularly, RUSLE modeling was implemented so as to calculate the soil loss rates considering the study area. According to the results, erosion mapping after the wildfire incidents seemed to present high soil loss values in comparison to their pre-fire state. Post-fire mapping displayed very high erosion values according to RUSLE modeling in all four areas of interest. Analyzing the results of the burned areas, moderate-high severity characterized the burned areas which were also found in large concentrations in all of them except Lavreotiki. Figure 9: Screenshot of the developed web app. The user interface is shown with the web map of the affected areas and the widgets. Within the boundaries of the affected areas, it could be observed that low severity values were present. Assessing the severity through the land cover, areas with moderate-high severity belong to the forest category of CLC 2018 thus making evident the ecological disaster but also the role of fuel that those areas constituted. The burned agricultural areas had moderate-low severity while the discontinuous urban fabric such as in Varympompi was characterized by mixed burn severity values. Another remark should be made about the terrain that affects the burned areas. More specifically, in most of the valley bottoms or higher altitudes, low severity values were found, or they were unburned due to their characteristics (e.g., low or no vegetation). We will proceed to the erosion risk analysis over the burned areas in which the soil loss and thus the erosion risk increased to a large extent, pinpointing areas that may face excessive soil loss in the future. The analysis of the factors has revealed the significant influence of topography on the erosion risk based on the \(LS\) factor, which makes clear the higher values of soil loss to the hydrographic network.