SHF 2007, Section de Glaciologie et Nivologie (15 et 16 mars 2007, Grenoble). Recent climatic and glacial evolution in Western Italian Alps, and Ciardoney glacier mass balance (Gran Paradiso range). CAT-BERRO D., MERCALLI L., 3 p.

In 2003-2006 period, mean temperature anomalies at Lago Valsoera weather station (2440 m, Gran Paradiso range) reached + 1.8°C over 1959-2002 mean values, and winter snow accumulation was 40 % below normal conditions.

Everywhere in Northern Italy last winter (December 2006 - February 2007) there has been the mildest ever recorded almost in last two centuries, as shown of winter temperature anomalies in Moncalieri (+ 2.6 °C compared with 1961-90 Dormais).

Hydrological season 2005-06 has been again warm and less snowy than normal in Western Italian Alps, therefore extremely unfavourable for alpine glacier, as all previous seasons since 2002-03  were.

In 2003-2006 period winter snow accumulation was 40 % below normal conditions (1959-2002 mean values) at Lago Valsoera weather station (2440 m, Gran Paradiso range).

In consequence of poor winter accumulation of snow and intense summer ice melting, glacier suffered huge mass lasses everywhere throughout this side of alpine range, for the fourth consecutive year. In 2005-06 season, net mass balance was -2.10 m w.e. at Ciardoney glacier,  -1.85 m w.e. at Grand Etret glacier (both in Gran Paradiso range), and -2.20 m w.e. at  Basodino glacier (Canton Ticino, Switzerland).

The comparison between mass balance data of south-western Alps shows that Ciardoney glacier is the most affected by ice losses, in consequence of its geographical position: cumulated mass balance in 1991-92 / 2005-06 period reached -19.7 m w.e., whilst Basodino glacier reached -6.7 m w.e. in the same period (snow accumulation in Canton Ticino mountains is usually much larger than in Gran Paradiso range). Moreover, its lower altitude and sunnier exposure explains higher mass losses than the ones measured at Grand Etret and Timorion glaciers.

If this negative trend continue in next decades - as foreseen by global and regional climate models - small glacier under 3200-3500 m, like Ciardoney one, may completely disappear before 2020-2030, in consequence of ice thickness losses of about 1-2 m / year.