Le frane connesse agli incendi boschivi: stato dell’arte e sviluppi futuri della ricerca anche alla luce dei cambiamenti climatici

Every year wildfire causes significant damage worldwide, leading to a severe modification in natural ecosystems and to economic losses. Moreover, wildfires can have profound effects on the hydrologic response of watersheds by changing the infiltration rates and erodibility of the soil: this is due to litter removal, ash deposition, soil physical alteration and generation or destruction of water repellent soils. Erosion rates in burned areas can increase more than 800 times with respect to the unburned situation; an increased susceptibility to debris flow, which may persist for several years after fire, it’s also affirmed. This work, on the one hand wants to signal that several Italian researchers have started a systematic study on these effects, on the other it wants to show the first results obtained in a case study in Piedmont. This region is affected by an increasing number of fires, as shown by statistics from the past 50 years. The case study concerns the area of Bussoleno, in the middle of the Susa Valley (Western Alps) and refers to phenomena that occurred in the spring / summer 2018 and related to the 2017 fires, when more than 4000 hectares burned on the slopes of the Rocciamelone, the mountain symbol of the Susa Valley. Several debris flows, triggered by the first heavy rains, hit the village, causing damage to houses and infrastructures and causing the evacuation of more than 200 people.