Ever smaller glaciers put the entire water system at risk

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January and February are two months which, lately, have little snow, although this year in the upper valley there is a fair amount. But then rainfall recovers relatively between March, April and May.

Last year, in this period the “situation was much more critical” recalls Pogliotti. There was much less snow, «then two big snow events allowed us to close the gap, providing “oxygen” until mid-summer». The same thing did not happen, however, in 2022, when, in fact, one of the worst water crises of recent times was suffered.

The winter is still long and it is early to be alarmed about the prospects for the current year, given that seeing snowfall at high altitudes until May is quite normal. Less normal, however, is the phenomenon which occurs more and more frequently over the years and which is also occurring in recent days: «At low altitudes (below 2,300 metres, so to speak, ed.) the snow is continuing to melt even in this period”. The scenario is becoming increasingly worrying, also because, as Paolo Pogliotti underlines, «in the Alpine chain in general, snow represents around 70% of the total runoff generated by the mountains as a water resource. 20-25% of the runoff depends on non-snow precipitation. Finally, under normal conditions, about 5% comes from glacial melting.”

This part – underlines the Arpa Valle d’Aosta biologist – should come to support in the final phase of summer (between August and September), when the melting of the snow has finished, it is hot and there is a great need for water. In recent years, however, glacial melting begins much earlier, even as early as June: if before it lasted a month, today it can last up to three months.” And so we return to the initial data: the thinning and progressive reduction of glaciers which “lose mass and become thinner”. Will they disappear completely? Leaving only meadows and pastures like the imaginary scenario of the legend concerning the Rutor? Difficult. But this is no consolation. Arpa also documents the retreat of the glacial front between the end of 1800 and 2012 of the Pré de Bard glacier in Val Ferret, now perched only at very high altitude, and of the Timorion glacier in Valsavarenche, which between 2005 and 2014 saw the front reduce by 40 metres.

With the current dynamics and without upheavals in a positive sense, the glaciers will continue to retreat until they nest at the highest altitudes – above approximately 3,500 meters – with very small dimensions. That buffer effect which was, and in part still is, fundamental for aquifers and the entire water system, for agriculture, livestock farming and also for industry will gradually disappear.

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