Morphological and geological traces of catastrophic floods are identified in valleys and watersheds morphology at the SE Altai, the floods are believed due to both catastrophic breaks through glacial lakes dams and to flow over watersheds. Landforms and sediments resulted from the floods are described, such as giant ripples, point-bars, bouder bars, terraces, evorsion holes, canyons etc., the features named by th author «Catastrophic-fluvial». The author once more suggsets the catastrophic discharge of proglacial lakes from Chuyskaya and Kuraiskaya basins, the floods had been traced into the Bashkaus valley. The catastrophic floods under consideration were not typical mudflows Judging from the landforms and deposits, the streams resembled giant «rivers» which transported and deposited their load according to usual laws of mountain rivers channel dymanics. The catastrophic floods due to ice-dammed lakes discharge are emphasized to be not unique events, but an important relief-forming f actor in glaciated mountains in the past.