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The Flims rockslide blocked at about 8,200 year BP the Vorderrhein river and so gave rise to the Paleo-Lake Ilanz. Shortly after the filling of the lake a severe flood event happened. The lake emptied not totally, but remained at a lower level for a long time. After important and perhaps even complete filling of the remaining basin with sediments the incision in the dam restarted and progressed in several smaller steps. Based on the detailed field works, the following sequence of the events can be envisioned: The Tamins rockslide occurred first, damming Lake Bonaduz; the Flims slide come down soon after and probably entered in this lake; at the same time the alluvium was mobilized and resedimented as Bonaduz gravel; Lake Ilanz was dammed to a level between 820 and 936 m for very short time; the dam broke partly and a flood happened; the remaining lake survived for a long time and was filled up; the Rhein river eroded the floodplain down to the actual level.