Flash floods triggered by the 15–17th March 2022 rainstorm event in the Atacama Desert mapped from InSAR coherence time series

This research provides examples of the impacts of flash floods of March 2022 rainstorm event on the Atacama Desert infrastructures investigated by means of InSAR coherence and in situ observations. The erosional processes associated with flash floods and the downstream distance they can travel are poorly known, preventing any mitigation strategy. Thus, a better understanding of sediment mobilization during high-intensity rainstorm events in the Atacama Desert is therefore essential to assess the impact of hydrogeomorphic hazards on critical infrastructures and ecosystems. The main findings are (i) the devastating role of small-scale (< 5 km radius) rainfall cells and their large impact on transport network infrastructures and (ii) the impact on infrastructure depended mainly on the transport capacity of the flows, which is in turn determined by the drained area upstream of the considered channel, and the rainfall intensity on these upstream areas. For example, water flows with high discharge could remove larger volumes of sediments, undermining and cutting roads. Such flows were frequent at ~ 26°S, while at ~ 22°S, they were limited to a few channels with large contributing areas. This resulted in extensive damage and required considerable time and money to recondition the road. In contrast, thinner mudflows with limited transport capacity tend to follow the roads and leave a thin deposit of mud that can be cleaned in a few days. The fact that roads transported mudflows over large distances and that mining infrastructure deflects natural drainages has been observed as a potential hazard to downstream infrastructures or inhabited areas.