Factors, determining the origin of debris flows on the southern slopes of the Crimean Mountains

Abstract

There is a lack of information about enabling and triggering factors of debris flows in the densely populated coastal slopes of the Crimean Mountains. In such respect, it is useful to reconstruct a chronology of historical debris flow events and correlate them with time series of relevant meteorological characteristics. We utilized dendrogeomorphological methods using 566 individuals of Pinus nigra for inferring age of 215 debris flow events. The oldest event is dated to 1701 and the highest decadal frequency of debris flows (20 events) is determined to 1940s. Long periods with anomalously low temperatures generating sufficient amount of debris are a major factor enabling debris flow. The dominant triggering factor for regional (multiply) debris flow events are long-term periods with above-average precipitations, but local (isolated) events are more related to short-term periods (~one month) with above-average precipitations.