Evolution and dynamics of Ghiacciaio Nord delle Locce (Valle Anzasca, Western Alps) from 1854 to the Present

Abstract

Taking into consideration the available documentation (maps and literature), a tentative is made to outline the evolution of Ghiacciaio Nord delle Locce since 1854. The unit examined is the third largest glacier in the Ossola valleys (within the Italian border); however the glaciological information on it has been scarce and unsatisfactory until the investigations of VAW/ETH, following to the outburst of Lago delle Locce in 1979. Some geographical information on the present Ghiacciaio Nord delle Locce, together with its glacial deposits, is first given. Then the map sources on which a part of the present investigation is based are carefully and critically reviewed, stressing on the problem of elevations. As no precipitation data for the upper, glacierized Valle Anzasca are available, some data from the ENEL dams in neighbouring Valle Antrona are presented: they show that there is a continuous decrease of precipitations since 1978, causing the present glacier retreat after a short time span of steady state and even short glacier advance. The available literature concerning Ghiacciaio Nord delle Locce is then critically reviewed and the investigations of the glaciologists of the VAW/ETH of Zurich, Switzerland, on Lago delle Locce and Ghiacciaio Nord delle Locce, are also recognized. Among the glaciological results of this research program, we underline the assessment of the dynamical behaviour of Ghiacciaio Nord delle Locce after sinking of Lago delle Locce level. A final section describes the present terminal and confluence condition of the investigated glacier.