In February, the Italian Snow Water Equivalent (SWE) deficit is at -64%: the worst data is recorded for the Apennines, but the scarcity of snow characterizes the entire peninsula, and in the Alps (fundamental for the water supply of several rivers, including the Po), the deficit is at -63%, comparable to last year’s
Let’s not lose sight of the snow: what is the situation in Italy at present? CIMA Research Foundation is monitoring the conditions of the Snow Water Equivalent (SWE), which represents a valuable indication of the amount of water storage we can rely on in spring and summer.
After the updates of December 2023 and January 2024, we continue here with the publication of the February data, to follow the situation and evaluate whether it improves or worsens depending on the meteorological conditions that arise. Unfortunately, today we report a deterioration: while a month ago the national SWE deficit was at -39% (still a discouraging figure), currently the deficit stands at -64%, a much more pronounced shortfall.
“This condition can be traced back to the mild and dry weather, especially in the second half of January, which exacerbated an existing deficit: according to our estimates, they led to the early melt of about 1 billion cubic meters of snow water in the second half of January. Unfortunately, snow scarcity has characterized our mountains for the past three years,” says Francesco Avanzi, researcher of Hydrology and Hydraulics Department of CIMA Research Foundation.
The worst conditions are in the Apennines where, one could say, the snow season is “missing”: the most striking example is that of the Tiber basin, which records an SWE deficit of -93%, with stationary conditions since November, when there was the last significant snowfall. More generally, for the Abruzzo region, which represents an index for the central Apennines, the deficit is at -85%, a significant worsening compared to January.
“Things are not improving outside the central Apennines either. The Simeto River, the main one in Eastern Sicily, records an SWE deficit of -61%, because after the first snowfalls in January, the rise in temperatures led to an early snowmelt,” says Dr Avanzi. “The snow in this area is only a small part of the national territory, but it is an indicator of a generalized drought in Sicily.”
Nor does the situation improve when looking at the Alps, where the overall deficit (-53%) is only slightly less pronounced than at the national level and very similar to that of last year at this time. “It is worth remembering that alpine snow is particularly important for Italy’s water supply, as it feeds several rivers, including the Po,” comments Dr Avanzi. “A basin that currently records an SWE deficit of -63% compared to the last 12 years.”
In short, the scarce snowfall of recent months has not been sufficient to offset the deficit – and this should not come as a surprise, because snow accumulation should be seen as a marathon, which must continue over time, and, as Dr Avanzi states, “One snowfall does not make a winter.”
“Statistically, the melting period begins in March. Recently, researchers from CIMA Research Foundation published two interdisciplinary articles, one with a legal perspective and the other scientific, highlighting how one of the main causes of the 2022 drought was the lack of snowmelt in spring and early summer,” concludes Dr Avanzi. “Monitoring the situation is therefore crucial to know what resources we can count on this year.”