How do Sahara dust deposits speed up Alpine snow and ice melt?

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Saharan Dust Accelerates Alpine Melt by Altering Snow Reflectivity

Saharan dust deposits significantly accelerate the melting of snow and ice in the Alps by reducing the reflectivity of the snow surface, causing it to absorb more solar heat. This phenomenon, observed between March and May, led to a premature loss of the protective snow cover on glaciers, leaving the underlying ice exposed to continuous heat from May through early September.
Reduced Albedo and Increased Heat Absorption

The influx of Saharan dust particles between March and May settled on the snow surface, creating a darker layer. This contamination lowered the snow's albedo, which is its ability to reflect sunlight. Consequently, the darkened snow absorbed more solar radiation, leading to a faster melting rate than would occur with clean snow.
Premature Loss of Protective Snow Cover

By early summer, the accelerated melting caused by the dust deposits had stripped away the glaciers' natural protective snow coating. This left the more vulnerable glacial ice directly exposed to the persistent heatwaves experienced throughout the European summer months. The continuous high temperatures from May until early September then severely impacted the exposed glacial ice.
Impact on Glacial Ice and Volume Loss

The combined effect of dust-induced melting and subsequent heatwaves led to a dramatic loss of glacial volume in 2022. The Swiss Alps, for instance, experienced a 6 per cent reduction in total glacier volume, shattering previous records. This process also exposed ice that had been frozen since at least the Roman era in some locations, such as the pass between the Scex Rouge and Tsanfleuron glaciers.

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How do Sahara dust deposits speed up Alpine snow and ice melt?

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