June 20, 2022

Heat Wave Leads to Rapid Glacier Snowcover Loss in Alps

Posted by Mauri Pelto

Grande Murailles Glacier, Italy (GM) in June Sentinel images. The yellow line is the glacier margin, the expansion of bare glacier ice from 1-3% of the glacier on June 10 to 20% of the glacier by June 18 is evident. The snowline is ~3200 m.

The heat wave during the last week that has impacted western Europe and the Alps has led to a predictable impact on glaciers (WMO, June 17, 2022). A month ago I focussed on the fact that heat waves and glaciers don’t usually go together; however, in the last several years an increasing number of heat waves have affected alpine glacier regions around the world (Pelto, 2022). In particular heat waves leave a greater portion of the glacier snow free, which enhances melting and mass balance losses. This is most pronounced when the heat wave occurs prior to or early in the melt season exposing bare glacier ice for a the bulk of the melt season.  Di Mauro and Fugazza (2022) identified an increasing melt season length and decreasing minimum albedo on glaciers in the Alp from 2000-2019, that does enhance melt. Here we utilize Sentinel 2 images from June 10 and June 18 to look at the rate of snowcover loss on three glaciers in the Alps.

On June 10 ~98% of Grande Murailles Glacier is snowcovered, 96% of Gries Glacier, and 100% of Sabbione Glacier is snowcovered. After eight days of unusual heat, the bare glacier ice regions have expanded notably, ~80% of Grande Murailles Glacier is snowcovered, 80% of Gries Glacier, and 65% of Sabbione Glacier remain snowcovered.  Grande Murailles Glacier drins west from Dent d”Herens just west of the Matterhorn. Sabbione Glacier feeds Lago del Sabbione a hydropower reservoir. Gries Glacier feeds Griessee a Hydropower reservoir. This rapid snowcover loss early in the summer is a particular issue given bare glacier ice melts ~50% faster than snowcover. This same scenario was observed last year in the Pacfic Northwest following a June Heat wave and in the Central Andes this summer 2022 after a January heat wave. In each case substantial mass balance losses occurred by summers end on these glaciers. This will continue to accelerate the fragmentation and loss of Sabbione Glaciers. This year the early season heat waves ability to strip snowcover from glaciers is enhanced by the limited snowpack that was received during the winter season that @VAW_glaciology has been reporting during spring monitoring of Swiss glaciers. This post will be updated on June 23 with additional images.

Gries Glacier, Switzerland (G) draining into the Griessee (Gs) in June 2022 Sentinel image. The terminus tongue, yellow arrow, extends below 2650 m to the terminus.

 

Sabbione Glacier, Italy (S) draining into Lago del Sabbione  (LS) in June 2022 Sentinel images. The west and south Sabbione Glacier are both entirely snowcovered on June 10. By June 18 most of the west Sabbione Glacier is bare glacier ice and 


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