Over the past decades, X-ray computed tomography (CT) has been increasingly applied in the geosciencescommunity. CT scanning is a rapid, non-destructive method allowing the assessment of relative densityof clasts in natural archives samples. This study focuses on the use of this method to explore instantaneousdeposits as major contributors to sedimentation of high-elevation lakes in the Alps, such as the Lake Lauvitelsystem (western French Alps). This lake is located within a very steep valley prone to episodic flooding andfeatures gullies ending in the lake. This variety of erosion processes leads to deposition of sedimentary layerswith distinct clastic properties. We identified 18 turbidites and 15 layers of poorly sorted fine sediment associatedwith the presence of gravels since AD 1880. These deposits are respectively interpreted as being inducedby flood and wet avalanche. This constitutes a valuable record from a region where few historical records exist.This CT scan approach is suitable for instantaneous deposit identification to reconstruct past evolution and maybe applicable to a wider variety of sedimentary archives alongside existing approaches