{"id":14473,"date":"2025-06-17T10:17:18","date_gmt":"2025-06-17T09:17:18","guid":{"rendered":"https:\/\/www.cimafoundation.org\/?p=14473"},"modified":"2025-06-17T10:20:30","modified_gmt":"2025-06-17T09:20:30","slug":"swe-intercomparison-snow-drought","status":"publish","type":"post","link":"https:\/\/www.cimafoundation.org\/en\/news\/swe-intercomparison-snow-drought\/","title":{"rendered":"Drought: reading summer in the disappearing snow"},"content":{"rendered":"\n

It is early June. Alpine resorts are getting ready for the summer season, and a group of researchers is heading up into the mountains\u2014not in search of cooler air, but of answers. Alongside skis, they carry probes. They are not looking for downhill slopes, but for scattered patches of snow across ridgelines and high-altitude basins. They move through irregular landscapes, where snow no longer blankets the ground evenly but retreats into white islands\u2014resilient remnants of a fading winter. <\/p>\n\n

From these traces begins the effort to anticipate both droughts and floods. Because snow is water. And when that snow shrinks, changes form, and becomes unpredictable, what is at risk is far more than a landscape\u2014it is a strategic, hidden water reserve on which rivers, lakes, crops, and life itself depend. <\/p>\n\n

Talking about snow in June, then, is not the eccentricity of passionate scientists. It is a scientific, technical, and environmental necessity. Because managing water resources begins here too: with a snowpack that changes form but remains central. With a group of researchers climbing into the mountains not only to measure snow, but to provide us with a clearer, deeper, and truer understanding of our water future. <\/p>\n\n

“Snow is the first building block of the Alpine water balance,” explains Francesco Avanzi, researcher at CIMA Research Foundation. “If we misjudge its quantity or properties, we miss the chance to anticipate droughts, manage floods, and more broadly, to design effective responses\u2014from reservoir operations to river flow forecasting.” <\/p>\n\n

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The context of the SWE Intercomparison 2025<\/h2>\n\n

It is from this renewed awareness that the 6th Snow Water Equivalent (SWE) Intercomparison took place on June 3\u20134 in Ch\u00e2tillon and Breuil-Cervinia, Aosta Valley, organized by ARPA Valle d’Aosta, CIMA Research Foundation, and Eurac Research. Two days of fieldwork and research involving over 50 experts from 21 institutions, including regional environmental agencies, universities, Civil Protection, forest corps, energy producers, and applied research centers. <\/p>\n\n

Over the years, the SWE Intercomparison has become a key technical and operational platform for studying the water resource stored in snow<\/a>, with a strong focus on measurement techniques. However, the particularly dry years of 2022 and 2023 brought attention to an emerging issue: the discontinuity of the snowpack and its growing occurrence even during periods typically characterized by consistent snow cover. <\/p>\n\n

The 2025 edition of the Intercomparison was conceived in this context. Its goal: to better understand the characteristics of patchy snow cover (snow patches)\u2014snow that does not uniformly cover the ground but appears in irregular, fragmented patches, strongly influenced by topography, solar radiation, wind, and temperature. <\/p>\n\n

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From continuous snow to snow patches: a paradigm shift<\/h2>\n\n
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\"Continuous
Fig. 1. Photograph of continuous snow cover. <\/figcaption><\/figure>\n\n
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“In typical winter conditions, snow is continuous, and our goal is to estimate the total water content at the watershed scale,” notes Simone Gabellani, Head of the Hydrology and Hydraulics Area at CIMA Research Foundation. “But when snow is patchy, as increasingly happens even during traditionally snowy periods, we need a paradigm shift. We must assess how much water is held in each patch, how their characteristics vary, and whether they can be monitored remotely\u2014perhaps even via satellite.” <\/p>\n\n

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\"Discontinuous
Fig 2. Snowpack in an advanced melt phase (and during snow drought years), characterized by irregular patch fragmentation due to combined effects of radiation, wind, and topography. Drone image acquired and processed by U. Morra di Cella (ARPA Valle d\u2019Aosta) within the Italian Space Agency (ASI) project SCIA (Development of Algorithms for the Study of the Cryosphere Using PrismA Imagery). <\/figcaption><\/figure>\n\n
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This change in perspective is urgent. As data show, patchy snow conditions are no longer the exception limited to the end of the melt season. In recent years, driven by rising temperatures and decreasing snowfall, snowpack discontinuity is occurring more frequently\u2014even in mid-winter. A new approach is needed\u2014one capable of addressing the complexity of a fragmented snowpack that behaves very differently from a continuous one. <\/p>\n\n

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A shared measurement protocol<\/h2>\n\n

During the Intercomparison, participants tested field protocols designed specifically for snow patches. After a preliminary satellite-based analysis to identify snow-covered areas, ten teams of five people each were equipped with dedicated instrumentation: snow depth probes (Hs), snow water equivalent (SWE) sampling kits, and GPS devices to geolocate measurement points. Each team traversed evenly spaced sampling lines, approximately 20 meters apart, measuring snow depth and identifying points of maximum accumulation, where snow pits were dug to perform more detailed SWE measurements. <\/p>\n\n

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The role of technology and the scientific community<\/h2>\n\n

“Working with patchy snow is not easy: we lack historical data, we lack models, we lack a shared vocabulary,” says Umberto Morra di Cella, UAV survey specialist and researcher at ARPA Valle d\u2019Aosta and CIMA Research Foundation. “But what we\u2019ve seen is that, despite their fragmentation, snow patches show certain recurring behaviors from year to year. This gives us hope: we can begin to build a robust scientific knowledge base\u2014provided we invest in observations and collaborative comparisons like this one.” <\/p>\n\n

<\/div>\n\n
\"Satellite
Fig 3. Sequence of satellite images (14\/05\/2017, 26\/06\/2019, 21\/05\/2020) showing the discontinuous distribution of the snowpack in late spring in an Alpine region \u2014 Contains modified Copernicus Sentinel data (2017\u20132020), processed by Eurac Research, CC BY-SA 3.0 IGO<\/a>. <\/figcaption><\/figure>\n\n
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In addition to the scientific and technical aspects, the Intercomparison also had strong collaborative value. The simultaneous presence of diverse institutions\u2014with complementary methods, instruments, and expertise\u2014enabled the comparison of measurement techniques, discussion of operational challenges, data validation, and the development of shared hypotheses. This growing community of practice is a fundamental pillar in addressing future water-related challenges. <\/p>\n\n

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From snow to drought: a transition we must predict<\/h2>\n\n

The challenge of patchy snow can no longer be postponed. Water resource management depends on our ability to predict how much and when snowmelt water will flow downstream. In a world increasingly affected by water crises, investing in the understanding of snow\u2014even (and especially) when it appears as scattered patches\u2014is an act of scientific and environmental foresight. <\/p>\n\n

This is why, on the World Day to Combat Desertification and Drought<\/a>, it makes perfect sense to talk about snow. Because the fight against drought also begins here: with a snowpack that changes form but remains essential. With a group of researchers climbing the mountains not only to measure snow, but to offer us a clearer, deeper, and truer understanding of our hydrological future. <\/p>\n\n

<\/div>\n\n
\n
\"Snow<\/figure>\n\n\n\n
\"Snow<\/figure>\n\n\n\n
\"Field<\/figure>\n\n\n\n
\"SWE<\/figure>\n<\/figure>\n","protected":false},"excerpt":{"rendered":"

It is early June. Alpine resorts are getting ready for the summer season, and a group of researchers is heading up into the mountains\u2014not in search of cooler air, but of answers. Alongside skis, they carry probes. They are not looking for downhill slopes, but for scattered patches of snow across ridgelines and high-altitude basins. […]<\/p>\n","protected":false},"author":4,"featured_media":14470,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[122,124,127],"tags":[89,87,88],"class_list":["post-14473","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-drought","category-hydrology-and-hydraulics","category-earth-observation","tag-droughts","tag-italy","tag-snow"],"acf":[],"_links":{"self":[{"href":"https:\/\/www.cimafoundation.org\/en\/wp-json\/wp\/v2\/posts\/14473","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.cimafoundation.org\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.cimafoundation.org\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.cimafoundation.org\/en\/wp-json\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/www.cimafoundation.org\/en\/wp-json\/wp\/v2\/comments?post=14473"}],"version-history":[{"count":3,"href":"https:\/\/www.cimafoundation.org\/en\/wp-json\/wp\/v2\/posts\/14473\/revisions"}],"predecessor-version":[{"id":14490,"href":"https:\/\/www.cimafoundation.org\/en\/wp-json\/wp\/v2\/posts\/14473\/revisions\/14490"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.cimafoundation.org\/en\/wp-json\/wp\/v2\/media\/14470"}],"wp:attachment":[{"href":"https:\/\/www.cimafoundation.org\/en\/wp-json\/wp\/v2\/media?parent=14473"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.cimafoundation.org\/en\/wp-json\/wp\/v2\/categories?post=14473"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.cimafoundation.org\/en\/wp-json\/wp\/v2\/tags?post=14473"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}