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Sulle Alpi europee, negli ultimi decenni, la temperatura dell'aria mostra un riscaldamento a un tasso medio di 0,3 °C/10 anni, un valore superiore al tasso di riscaldamento globale che è di 0,2 °C/10 anni. L'ambiente periglaciale alpino è particolarmente importante per diversi aspetti (es. energetico, ecologico e turistico). Tuttavia mancano studi specifici e aggiornati relativi alle tendenze della temperatura in questo ambiente. Per colmare questa lacuna sono state analizzate le tendenze delle temperature per il periodo 1990-2019. L'ambiente periglaciale delle Alpi ha mostrato un tasso di riscaldamento di 0,4 °C/10 anni, 0,6 °C/10 anni e 0,8 °C/10 anni rispettivamente per la temperatura media, massima e minima. Questi tassi di riscaldamento sono superiori a quelli osservati per l'intera area alpina. Nel 2050 si prevede l'estinzione di molti ghiacciai delle Alpi al di sotto dei 3000 m di altitudine e tutte le aree precedentemente occupate dai ghiacciai diventeranno periglaciali.

Nell'ambito di un lavoro di tesi in collaborazione tra il Dipartimento di Scienze della Terra dell' Università di Torino e il gruppo di ricerca GeoClimAlp del CNR-IRPI, è stata analizzata la correlazione tra instabilità dei versanti ed evoluzione della criosfera per un settore delle Grandes Murailles. Seguendo i criteri proposti per la "Carta delle litofacies in funzione dell'instabilità della Valle d'Aosta" (Progetti "IFFI "e "Risknat"), è stata realizzata una classificazione dello stato reologico del substrato roccioso, integrata dalla caratterizzazione geomorfologica dell'area. L'interpretazione si è basata su dati di terreno e riprese aeree. Servendosi di immagini storiche e ortofoto digitali è stata anche analizzata l'evoluzione degli ambienti glaciale e periglaciale dell'area. In particolare, oltre alla ricostruzione cronologica di alcuni eventi di frana, sono state mappate le variazioni dell'estensione del Ghiacciaio di Mont Tabel a partire dalla Piccola Età Glaciale (1850 circa) e più dettagliatamente fra il 1954 e il 2012. Dalla Alpine Permafrost Index Map (Boeckli et al., 2012) è stata infine ricavata la probabilità di occorrenza di permafrost nell'area indagata. La correlazione tra le caratteristiche geologico-geomorfologiche del versante e l'evoluzione della criosfera ha permesso la formulazione di ipotesi sull'evoluzione futura del paesaggio geomorfologico nel contesto dei cambiamenti climatici in atto.

Le relazioni tra la temperatura dell'aria e le frane in alta quota sono importanti da conoscere, ma sono molto difficili da studiare. Questa difficoltà è causata principalmente dalla mancanza di stazioni meteorologiche posizionate alle quote dei distacchi. La diminuzione della temperatura dell'aria con la quota in atmosfera libera è di circa 0,6 °C /100 m, ma sui versanti montuosi questa diminuzione varia in relazione a diversi fattori locali, sia geografici e sia climatici. Un metodo affidabile per stimare la temperatura dell'aria a quote elevate consiste nell'utilizzare il gradiente altitudinale di temperatura calcolato localmente (ATLR) e applicarlo in alta quota. Per calcolare l'ATLR, abbiamo utilizzato i dati acquisiti dalle stazioni meteorologiche automatiche ubicate ad un'altitudine superiore a 2500 m (Centro Funzionale Regione Autonoma Valle d'Aosta). I principali risultati sono riportati negli Highlights. Questo lavoro ha messo in luce che non è sufficiente migliorare le conoscenze sulla temperatura dell'aria, ma è anche necessario conoscere le condizioni termiche dei diversi litotipi coinvolti in questi processi. Per ulteriori informazioni: https://cnrirpicervinia.panomax.com/plateaurosa Questo contributo è dedicato alla professoressa Simona Fratianni.

Osservazioni, dati e risultati della campagna glaciologica 2019 per i quattro ghiacciai dell'Arguerey e del Breuil, meridionali e settentrionali. Drastiche riduzioni areali e volumetriche dei ghiacciai osservati.

Miniature temperature data loggers, metrological traceability of measurements, thermal properties of rocks. An open-air laboratory to study one of the most important triggering factors of rockfalls in the European Alps: temperature; permafrost and a metrology lab at 3000m.

Rockfalls are one of the most common instability processes in high mountains. They represent a relevant issue, both for the risks they represent for (infra) structures and frequentation, and for their potential role as terrestrial indicators of climate change. This study aims to contribute to the growing topic of the relationship between climate change and slope instability at the basin scale. The selected study area is the Bessanese glacial basin (Western Italian Alps) which, since 2016, has been specifically equipped, monitored and investigated for this purpose. In order to provide a broader context for the interpretation of the recent rockfall events and associated climate conditions, a cross-temporal and integrated approach has been adopted. For this purpose, geomorphological investigations (last 100 years), local climate (last 30 years) and near-surface rock/air temperatures analyses, have been carried out. First research outcomes show that rockfalls occurred in two different geomorphological positions: on rock slopes in permafrost condition, facing from NW to NE and/or along the glacier margins, on rock slopes uncovered by the ice in the last decades. Seasonal thaw of the active layer and/or glacier debutressing can be deemed responsible for slope failure preparation. With regard to timing, almost all dated rock falls occurred in summer. For the July events, initiation may have been caused by a combination of rapid snow melt and enhanced seasonal thaw of the active layer due to anomalous high temperatures, and rainfall. August events are, instead, associated with a significant positive temperature anomaly on the quarterly scale, and they can be ascribed to the rapid and/or in depth thaw of the permafrost active layer. According to our findings, we can expect that in the Bessanese glacierized basin, as in similar high mountain areas, climate change will cause an increase of slope instability in the future. To fasten knowledge deepening, we highlight the need for a growth of a network of high elevation experimental sites at the basin scale, and the definition of shared methodological and measurement standards, that would allow a more rapid and effective comparison of data.

Campagna glaciologica 2017. Osservazioni generali per il gruppo Miravidi-Lechaud

Rock and debris temperature variability in alpine environment: a new measurement approach

Freeze-thaw action induces both rock weathering and mass wasting, destabilizing rock and debris slopes in high mountain regions. Matsuoka, in 1990, defines an Effective Freeze-Thaw Cycle (EFTC) as a fall below -2 °C of the rock surface temperature followed by a rise above +2 °C. Rock temperatures in alpine environments are strongly inuenced by slope inclination, slope aspect, local topoclimatic conditions (including seasonal snow cover), and thermal properties of the rock.

osservazioni sullo stato dei ghiacciai, misure di variazione delle fronti glaciali, fotografie e rilievi geomorfologici, prelevamento di campioni di roccia

Sono stati osservati i seguenti 4 ghiacciai delle Alpi Marittime: Clapier, Peirabroc, Maledia, Gelas. Il Ghiacciaio del Clapier è il ghiacciaio ubicato più a meridione di tutti i ghiacciai alpini. Sono state effettuate fotografie, rilievi e sono stati prelevati dei campioni di roccia (Gneiss).

The Bessanese glacial basin (Lanzo Valleys), has been chosen to become an "high mountain open-air laboratory" for the investigation of geomorphological processes in a context of climate change. In the present research several activities were carried out: investigation of rock and air temperature variability by 7 micro temperature data loggers and an Automatic Weather Station (AWS); identification of rockfall events by the analysis of different data sources; evaluation of glacier evolution considering both areal and thickness changes. It emerges that the study area is characterized by 3 main lithologies presenting different physical properties (colour, density and specific heat capacity) and showing differences in their thermal regime mainly affected by lithology and solar exposure. Moreover, during the AWS operation period, air temperature shows significant warming trends. On the other hand, rockfall events have been identified in the summer months and several geomorphological evidences highlight a considerable rockfalls activity mainly affecting the Bessanese rockwall. Finally, since the end of the Little Ice Age the Bessanese Glacier experienced a significant shrinkage (disappearance of the left lobe and important retreat of the right one) and maximum mass loss of about 60 m. Links among the different considered aspects have been found and their detailed study will help in enhancing the knowledge on the various effect of the climate change in high mountain areas.

Air temperature is one of the most important variables of high altitude mountain climate, however it is often difficult to measure it because of the shortage of active weather stations. In order to estimate this variable locally and accurately, it may be useful to refer to data from the lowest altitude weather stations and to apply the local vertical thermal gradient. From semi-hourly or hourly temperatures, monthly and seasonal vertical thermal gradients were calculated. In all cases, we obtained different values from the standard thermal gradient: they oscillate on average between -1.2 ° C / 100 m and 1.9 ° C / 100 m. The average monthly and seasonal values vary considerably between the pairs of stations studied. A better knowledge of the temperature of high altitude zones allows the realization of models of spatial distribution of temperatures at fine scales, which are crucial for scientific research.

The ongoing debate about the effects of global warming in glacial and periglacial areas implies a lack of knowledge about the role of climate elements on the cryosphere dynamics. Slope instability processes are one of the major indicators of a changing climate at high elevation, but we know little about the relation between climate and slope instability processes. In this work, we briefly introduce our activities and developments on this issue. We collected more than 440 slope failures events at high-elevation sites in the Italian Alps from year 2000 on. By means of a statistical-based method, we detect the possible anomalies of the climate variables at the date when slope instability events occurred. Based on the preliminary outcomes of this work, we expect to be able to identify the variables which acted as potential triggers/drivers of slope instability processes in (peri)glacial and permafrost areas.

The Alpine environment and in particular the cryosphere, is responding quickly and with great intensity to climate change. Temperature increase observed in the Alps urge the scientific community to study not only air temperature but also rock temperature, to deepen the knowledge about thermal properties of the potentially unstable geological materials. The metrological traceability of measurements is fundamental for data comparability in space and in time and this can be achieved by the use of calibrated instruments and with the evaluation of measurement uncertainties. Here we present some preliminary results of rock-face temperature analysis based on data acquired at high-elevation sites, by means of sensors with documented traceability to International System of Units Standards and evaluated measurement uncertainty. We found and quantified a strong difference in the hourly rate of temperature increase between air and rock. During summer rock temperature grows more than 8 times over air temperature.

Osservazioni ai ghiacciai di Arguerey meridionale, Arguerey settentrionale, Breuil meridionale e Breuil settentrionale (La Thuile, Aosta)

In this presentation we show the preliminary results of the RiSt project

The evolution of the Mont Tabel Glacier over the last 150 years

Il progetto RiST e il laboratorio all'aperto della Bessanese: primi risultati e prospettive

The analysis of glacial and periglacial morphodynamics and the study of past climate changes are important tasks for scientific and management purposes within recently deglaciated areas. Climate changes and related effects occurring in the last decades cause uncertainties on the survival of glaciers and affect stability of mountains. A systematic study of natural hazards related to glacial and periglacial morphodynamics of the Western Alps in Italy and the Coast Mountain and the Cordillera in Canada started only in the early 1990s. Since then, several instability phenomena of these glacial and periglacial environments have been analyzed, as well as their relationship with the climatic and environmental changes taking place since the end of the Little Ice Age. From the beginning of the 2000s, it became clear that environmental changes related to global warming were accelerating so quickly in high elevation and glaciated mountains. Within this perspective, we started an international effort to collect data and compare geomorphic processes occurring in the high mountains of two distant geographic areas, but with similar physiographic characteristics. Aims was to provide scientists and local administrations with the most advanced knowledge and tools to deal with climate-related instability events occurred in glacial and periglacial areas of the Italian Alps and of Western Canada, such as landslides, debris flows, glacial lake outburst floods, ice avalanches. We identified the types of instability mainly conditioned by climate change and discussed hazard scenarios. Methodological approaches used in Italy and Canada for studying the impacts of degrading permafrost and glacier ice loss on mountain environments were compared, and strategies for communication and dissemination of results were addressed. Studies have shown differences and similarities among the two areas, which highlight the effects of regional/local physiography and climate and, at the same time, confirm the global scale of the changes underway.

Descrizione delle caratteristiche termo-pluviometriche presenti nel gruppo montuoso Miravidi-Lechaud, Valle d'Aosta.

State of the art The Alpine environments, and in particular the high-elevation sites (H-ES), are responding quickly and with great intensity to climate warming (CW). Cryosphere (including permafrost) degradation is one of the main effects and heavily conditions morphodynamic processes (MP). In this context, the relationships between CW and MP at H-ES are complex to be studied. The knowledge of the thermal conditions of the different materials (air, rock, debris, soil, ice, water) at H-ES are few. Furthermore, available data are often acquired with sensors and acquisition chains with unknown uncertainty of measurement. Main objectives i) Increase knowledge about the thermal conditions of the different geological materials at H-ES; ii) Measure temperature at H-ES by means of sensors and acquisition chains with known uncertainty of measurement; iii) Use the Bessanese glacial basin (Graian Alps, Italy, municipality of Balme*) as an open air experimental laboratory to study the variability of the thermal conditions of different materials (air, rock, debris, soil, ice, water) that are involved in the MP. Partnership - CNR-IRPI, GeoClimAlp research group - Meteomet Consortium (see box at the bottom) - Comune di Balme - Rifugio Bartolomeo Gastaldi Project co financed by Fondazione CRT

RiST Project: Il bacino glaciale della Bessanese come laboratorio di ricerca all'aperto. Presentazione di un anno di attività, con particolare riferimento ai dati di temperatura in roiccia acquisiti mediante sensoristica con conosciuta riferibilità metrologica delle misure e con conosciuta incertezza.

risultati della campagna glaciologica 2015: osservazioni ai ghiacciai Arguerey e Breuil (La Thuile, Aosta)

RiST Project: Ricerca Scientifica e Tecnologica nel bacino glaciale della Bessanese (Balme, TO). Presentazione del primo anno di attivirtà sperimentale.

Osservazioni generali per i ghiacciai del gruppo Miravidi-Lechaud per la campagna glaciologica 2015

Natural instability processes like landslides, muddebris flows and floods are the most frequent geohydrological phenomena in Piedmont (north-western Italy). They can involve urbanized areas and consequently can generate risk-prone areas according to the geomorphological features of the territory. Piedmont has been hit by five relevant events in the last 20 years (September 1993, November 1994, October 1996, October 2000 and May 2008): geohydrological processes have caused fatalities and damage for several hundred million Euros. The aim of this study is to evaluate the spatialtemporal distribution of the natural instability processes over the past two centuries and to relate it to the current land planning: that can permit to identify the hazard-prone areas that can become riskprone areas when urbanized areas are involved. The study area (1,200 km2) is located in the north-western Italy (Piedmont). The methodology has been carried out by the following steps: a) analysis and interpretation of historical documents gathered in the Archive of the Research Institute for Geo-Hydrological Protection of the National Research Council (CNR-IRPI). In the IRPI of Turin, in fact, there is the richest Italian archive of information about natural instability processes occurred in the north of Italy; b) drafting of descriptive records into a geodatabase; c) localization of the natural instability processes using GIS; d) synthesis and data processing and e) case studies: comparison between geomorphological effects and the current land planning. The gathered documents of 24 municipalities were deeply analyzed and about 900 records were filled and georeferenced. They have permitted to have a more detailed picture of the main natural instability processes which affected the examined area and the relative damage. This study has highlighted that a correct territorial planning for the prevention and mitigation of geohydrological risk cannot ignore the wealth of information that can be obtained from historical research.

caratterizzazione climatica per l'anno 2014

This work aims to illustrate the evolution of the Arguerey and Breuil glaciers (La Thuile, Aosta Valley), from the end of the Little Ice Age (LIA) to the years 2000s. Glacier extent for specific time steps (1850, 1929, 1961, 1975, 1999, 2005) has been derived from topographic maps, orthophotos, and from data collected by the Italian Glaciological Committeeand by the Glariskalp Project. Acquired data were stored in a GIS, in order to allow a quantification of glaciers change over time. At the end of the LIA the Arguerey Glacier had an areal extent of about 2.26 km2: in 2005 this glacier appeared fragmented in two main bodies, covering a total area of about 0.44 km2, with a reduction of 81% of the glaciated area over 150 years. At the end of the LIA the Breuil Glacier had an areal extent of about 3.39 km2: in 2005 the glacier was subdivided in two bodies, for a total area of about 0.69 km2, with a reduction of 80% of the glaciated area in 150 years. A detailed reconstruction of glacier change through time will be provided. The above data will be completed with the most updated information gathered during the most recent glaciological surveys realized in the framework of the Italian Glaciological Committeeactivities. The evolutionary framework of the glaciers will be completed with a climatic characterization of the area in order to know the main climate elements and the monthly or seasonal variability of these. This work, carried out in the framework of the NextData project, aims to contribute to the knowledge of recent glacier evolution in the northwestern Italian Alps, also in support of studies on the impacts of climate change on high-altitude environments and resources.

Nel presente lavoro vengono analizzate la variabilità climatica e l'evoluzione dei ghiacciai delle Alpi Piemontesi centro-meridionali dalla fine della Piccola Età Glaciale (PEG) ai giorni nostri. Durante il periodo 1950-2012 le temperature medie mensili riferite ai valori massimi e minimi hanno evidenziato una significativa tendenza all'aumento. Dopo il 1980, i trend positivi sono stati ancor più evidenti ed hanno riguardato soprattutto le temperature minime. Le precipitazioni non hanno mostrato segnali netti, anche se per alcune stazioni si sono osservate diminuzioni statisticamente significative per quanto riguarda il periodo invernale. Dalla fine della PEG al 2006, il numero di ghiacciai si è ridotto notevolmente, passando da 96 a 40 e la riduzione areale è stata di circa il 78%. Il presente lavoro mette in evidenza come l'aumento delle temperature minime agisca sulla riduzione delle aree glacializzate non come unica causa ma come acceleratore di un processo già in atto dalla fine della Piccola Età Glaciale.

Campagna glaciologica 2014: osservazioni ai ghiacciai Arguerey e Breuil (La Thuile, Aosta)

I ghiacciai sono tra i migliori indicatori terrestri del cambiamento climatico. La conoscenza dell'evoluzione nel tempo delle loro dimensioni e della loro morfologia costituisce un elemento indispensabile per lo studio degli ambienti di alta quota e per la comprensione delle modificazioni indotte dal cambiamento climatico in atto. A tale scopo, gli archivi di dati glaciologici stanno riscontrando un interesse in continua crescita a livello internazionale. Nell'ambito del Progetto Alcotra "GlaRiskAlp" è sorta l'esigenza di disporre di un data base relativo ai ghiacciai piemontesi, il quale consenta un accesso rapido ed efficiente all'informazione disponibile per le finalità del progetto. Il presente lavoro descrive la struttura e le funzioni di questo database relazionale, strumento semplice nell'utilizzo, basato su tecnologie web e realizzato mediante software open source.

In this paper we present a web-based relational database on the main levee breaches of the Po river (Northern Italy), which have occurred since the year 1880 until today in the section of the river between the towns of Zerbo (Pavia province) and Serravalle (Ferrara province). The database contains more than 200 fact sheets that show the information for each levee failure. For each fact sheet are attached documents, recent maps and historical maps. The access at the database is free of charge and the web interface includes 88 pages that users can access through a simple and intuitive graphical user interface. The relational database and web application were developed through free open source solutions (Apache, MySQL and PHP). This database may provide a valid support at the environmental protection agencies and a valuable technical aid during the forecasting and monitoring phases of rainfall events and help in the design of defense interventions directed at the prevention and mitigation of hydraulic and geologic risk.

One of the impacts of climate warming in recent years is the evident increase of the number of rock fall occurrences at high elevations. With few exceptions, these events have small magnitudes and thus are rarely reported and documented, even less so in the past. Therefore it is difficult to use a statistical approach to analyze of the relationships between climate warming and rock slope instability. On the other hand, it is often difficult to carry out a time analysis of meteorological conditions responsible for rock fall triggering, considering that very few automatic weather stations (AWS) are located in the areas and in the altitudinal range that are affected by cryosphere degradation (i.e. above c.a. 3,000 m elevation in the Alps), and that climatic conditions in high elevation environments are spatially and temporally variable. The present study addresses the above-mentioned issues through analysis of a series of small rock falls that occurred in the last 10 years on the Matterhorn and surrounding rock slopes. A specific focus is temperature: we present a preliminary analysis of the spatial and seasonal variability of the vertical temperature gradient in the Conca di Cervinia, where the Matterhorn is located, to illustrate the uncertainty in estimates of the thermometric conditions at high elevation rock fall sites.

The radical changes caused by glacial masses in the past and still present are accompanied by equally important morphological changes in the previously glaciated areas. A first attempt of quantifying the effects of climate change in the Anthropocene was carried out for the Orco and Lanzo Valleys, through a detailed geomorphological analysis and interpretation of traditional aerial photos and digital orthophotos, available at a variety of scales and for different years. This analysis showed that between 1850 and 2006 the overall number of glaciers in the studied area has decreased by 64% which correspond to a reduction of glaciated area of 78% compared with the glacier extent during the peak of the LIA (58.8 km2) (Lucchesi et al., 2014). The areas of recent deglacialization are currently characterized by the outcropping of new large rock surfaces, by extensive and impressive moraines and till, or by the presence of lakes. Overall 13.5 km2 (corresponding to 28%) of the areas of recent deglacialization are characterized by the outcropping of rock, 33.9 km2 (71%) are covered by glacial deposits (till), fluvioglacial or gravitational sediments (slope debris, landslides) and 0.6 km2 (1.3%) are occupied by lakes in 2006. The environment of recent deglacialization is morphologically very young and dynamic, more exposed than others to extremely fast remodeling processes, especially for the areas covered by glacigenic deposits. For instance, on 24 September 1993, after an intense rainstorm, a large portion (800,000 m3) of the frontal moraine of the Mulinet Glacier was removed by a huge debris flow that traveled 4.5 km downstream. Nevertheless, recently deglaciated areas are in part affected by the presence of a more or less pervasive and continuous permafrost (Mair et al., 2011). The presence of permafrost has a stabilizing effect on rock and debris slopes. Under a warming climate, permafrost degradation can become one of the most relevant factors contributing to the development of instability processes (in particular rock falls and debris flows). For this work, we met the geomorphological information obtained for the deglaciated areas (type and extent of outcropping materials), with the permafrost distribution map realized in the framework of the PermaNet project for the European Alps. As a result, we were able to make a first estimate of debris areas and volumes prone to instability, or ready to be mobilized by surface water runoff.

Climate change in the Greater Alpine Region is seriously affecting permafrost distribution, with relevant consequences on slope stability. In the Italian Alps, the number of failures from rockwalls at high elevation markedly increased in the last 20-30 years: the consistent temperature increase, which warmed twice than the global average, may have seriously influenced slope stability, in terms of glaciers retreat and permafrost degradation. Moreover, the growing number of tourists and activities in alpine regions (in particular in the Dolomites) made these areas particularly critical in relation to natural hazards. In this light, an integrated short-term geomorphological and climatic analysis was performed, in order to better comprehend the impact of main climate elements (especially temperature and precipitation) on slope failures in high mountain areas. In this contribution, we focus on three recent slope failures occurred at high elevation sites in the Dolomites (Northeastern Italian Alps), declared a UNESCO World Heritage Site in August 2009. We describe here three important rock falls occurred in the autumn 2013: 1) the Sorapiss rock fall, on 30 September 2013; 2) the Monte Civetta rock fall, on 16 November 2013; 3) the Monte Antelao rock fall, on 22 November 2013. The Monte Civetta rock fall damaged some climbing routes, while the other two landslides did not cause any damage or injury. Despite the limited volume involved, these three events represent an important warning sign in the context of ongoing climate change. Geomorphological information about the rock fall sites were combined with the climatic data acquired from the meteorological stations surrounding the slope failure areas. A short-term climatic analysis was performed, with the aim of understanding the role of the main climatic elements in the triggering of natural instability events in this area and in the Alps in general.