One of the most documented examples of landslides in karstic rocks was the 1963 Vajont translational slide in northeastern Italy, which moved into a reservoir, thus causing a huge impulse water wave that overtopped the concrete dam leading to a sudden catastrophic flood destroying some villages and killing over 2000 peoples.
I believe you are considering a naturally formed dam across a river? which might be due to a previous slope failure or rockfall? then it fails due to internal erosion or because of its unstable form (by shear) causing damage to nearby structures on the downstream side or if it doesn't fail may be due to accumulation of river water it may cause a rise in the river level and flood the upstream side? either way, it is a rare phenomenon I suppose.
Many models have been established to simulate the process and even predict the flood area, which is great. But there's still a lack of model that simulates the disaster chain.
My research is available on @ResearchGate: https://www.researchgate.net/publication/321016753_Madi_River_Nepal_Landslide_dam_outburst_flood_risk_management?utm_source=twitter&rgutm_meta1=eHNsLXB2cmRxK2hyR2N1RHVJb1Nob0JpVGpKb0RlTW15WEtKZkh2SWg0QmExUDlDYlRlWlJxckkwa0tsOTRqQUxNUW9HR1NkYldacy9Ja1JXcTQ4YUlMZmRvMD0%3D #LandslideDamOutburstFlood #RiskManagemnt #MadiRiverNepal