On September 15, 2022, a stationary V-shaped thunderstorm formed over the Apennines in central Italy, dumping up to 419 mm of rain in just 9 h near the town of Cantiano, causing widespread severe flooding and landslides over an area of 5000 km2. This study highlighted the relationships between the landslides mapped after the event in the mountainous areas with the highest rainfall intensity (E-LIM inventory), the surrounding territory, and the rainfall event itself. Then, their comparison with those of a detailed mapping conducted before the event at the national level (IFFI inventory), based on a collection of data accumulated over the years, allowed for an initial examination of the variability in the territory’s response to an event outside the typical climatic conditions upon which the spatial information regarding landslide risks is currently founded. The analyses were conducted over an area of 550 km2, considering the findings deriving from field surveys and a detailed GIS analysis. These landslides were concentrated in areas with rainfall between 285 and 419 mm in 24 h, corresponding to carbonate lithologies. Relatively high values in the last class of precipitation (45–125 mm) are instead related to the predominant occurrence of Quaternary slope debris. The main landslide types are debris flow, debris slide and debris slide-flow, and almost ¾ of the overall dataset are new landslides. In cases of overlay with already mapped areas, eighty per cent of the E-LIM debris flows correspond to roto-translational slides and slow earth flows recorded in the IFFI inventory. The new landslides did not develop along slopes with aspects significantly different from the oldest landslides, and the occurrence of both pre-existing and post-extreme event landslides was determined by geology and morpho-structural settings.