Volcan Overo is a 4619 m high Andean mountain in Argentina with a relatively low sloped broad volcanic summit region above 4000 m that hosts a glacier complex that is shrinking and fragmenting. La Quesne et al (2009) observed significant annual thinning in the latter half of the 20th century on nearby glaciers in Argentina and Chile. A sharp increase in mass loss on Central Andean glaciers after 2009, including the Volcan Overo region, was reported by Ferri et al (2020). Here we examine Landsat images from 1986-2022 to identify longer term changes of the glacier and Sentinel images from 2018-2024 illustrating the persistent lack of an accumulation zone leading to recent changes, including the impact of the January 2023 heat wave (Washington Post, 2022). The persistent lack of an accumulation zone during the 2018-2024 period, highlighted in images below, in which no snow was retained as firn, indicates the glacier cannot survive (Pelto, 2010).
Volcan Overo in Landsat images from 1986-2022 illustrating area loss and fragmentation.
In 1986 there are four discrete glaciers around the caldera, covering ~12 km2 the largest E around the summit ranges in elevation from 4200-4500 m. D is an isolated area at 4000-4100 m. A,B and C is a single glacier extending from 3900-4300 m. F is an area of rapidly diminishing glacier ice.
In the early February image snowcover is good across all ice areas except F. In 2003 there is limited evident change with good snowcover across all except D. By 2013 A, B and C have fragmented into three separate glaciers and F is nearly gone. Only E has significant snowcover.
In 2022 C and D in the Landsat images have declined to less than 50% of their 1986 area, the overall Volcan Overo glaciated area has declined to ~8.1 km2. It is not quite mid-summer on January 8, 2022 yet all snowcover has been lost from the glaciers of Volcan Overo. The glacier remnants at F are now gone.
The impact of heat waves in 2022 and 2023 has taken its toll on the glacier.
From a Glaciers Perspective 