A dendrochronological assessment of snow avalanche events in Río de Las Vueltas, Santa Cruz, Argentina

RADINS, MARCOS; MARCOTTI, EUGENIA; BONADA, ANABELA; VILLALBA, RICARDO; BIANCHI, LUCAS OSVALDO; RODRIGUEZ PALMIERI, MARIA PAULA

Mendoza

Congreso; Ameridendro 2016 - Third American Dendrochronology Conference; 2016

IANIGLA - Tree Ring Society

now avalanches are a common disturbance that affects large portions of the Nothofagus pumilio subalpine forest in the southern Patagonia Andes. However, detailed studies of avalanches are hampered by the lack of historical records in the region. In this context, tree-ring derived reconstructions of avalanche events are a valuable alternative to analyze the influence of this disturbance on the structure and composition of the N. pumilio forests. In this contribution, we present recent advances in avalanche reconstructions in the Río Toro and Río Milodón valleys, in the Las Vueltas basin, Santa Cruz, Argentina. Our reconstruction is based on 312 cross-sections and increment borer samples. The year of each event was determined by dating scars and abrupt growth releases and suppressions related to avalanches. Avalanches were found to be frequent over the past 100 years, when 10 major events were identified. The most intensive avalanches were observed during the years: 1966, 1971, 1985, 1998, 2002 and 2012. The occurrence of avalanches since 1965 coincided with years of abundant winter precipitations. Avalanches took place in both valleys during the years 1966 and 1985. These early results are a significant contribution to the study of avalanching in the Las Vueltas basin.