The Echaurren Norte Glacier is a reference glacier for the World Glacier Monitoring Service (WGMS) network and has the longest time series of glacier mass balance data in the Southern Hemisphere. The data has been obtained by the direct glaciological method since 1975. In this study, we calculated glacier area changes using satellite images and historical aerial photographs, as well as geodetic mass balances for different periods between 1955 and 2015 for the Echaurren Norte Glacier in the Central Andes of Chile. Over this period, this glacier lost 65% of its original area and disaggregated into two ice bodies in the late 1990s. The geodetic mass balances were calculated by differencing digital elevation models derived from several sources. The results indicated a mean cumulative glacier wide mass loss of −40.64 ± 5.19 m w.e. (−0.68 ± 0.09 m w.e. a⁻¹). Within this overall downwasting trend, a positive mass balance of 0.54 ± 0.40 m w.e. a⁻¹ was detected for the period 2000–2009. These estimates agree with the results obtained with the glaciological method during the same time span. Highly negative mass change rates were found from 2010 onwards, with −1.20 ± 0.09 m w.e. a⁻¹ during an unprecedented drought in Central Andes of Chile. The observed area and the elevation changes indicate that the Echaurren Norte Glacier may disappear in the coming years if negative mass balance rates prevail.

Alluvial fans are episodically affected by the distributary dynamics caused by extreme biphasic flow processes. The solid-fraction component of biphasic flows is generally represented by inorganic sediment, but these events may also carry significant amounts of large wood. The aim of the study was to assess on a physical alluvial fan model the randomness of morphodynamical processes and exposure associated to a set of specific loading conditions and at exploring how these patterns change if large wood is added to the biphasic mixture in a fixed proportion of the solid fraction. The experiments were conducted varying systematically the total volume, the sediment fraction of the biphasic mixture and the applied stream power. Two sets of experiments were run, either with and without a fixed proportion of the solid fraction constituted by large wood. Our results confirm that the exposure associated to specific loading conditions exhibits a remarkable randomness, that the applied stream power has a decisive effect on the variability of exposure and that the fixed portion of large wood strongly interfere with the distributary dynamics on alluvial fans.