Drainage of ice-contact MiageLake (Mont Blanc Massif, Italy) in September 2004

Authors

  • Philip Deline Laboratoire EDYTEM, CNRS-Université de Savoie, Le Bourget-du-Lac, France Author
  • Guglielmina Diolaiuti Dipartimento di Scienze della Terra, Università di Milano, Milano, Italy Author
  • Martin P. Kirkbride Department of Geography, University of Dundee - Nethergate, Dundee, Scotland, United Kingdom Author
  • Giovanni Mortara CNR - Istituto di Ricerca per la Protezione Idrogeologica, Sezione di Torino, Torino, Italy Author
  • Mauro Pavan Dipartimento di Informatica e Scienze dell’Informazione, Università di Genova, Genova, Italy Author
  • Claudio Smiraglia Dipartimento di Scienze della Terra, Università di Milano, Milano, Italy Author
  • Andrea Tamburini Enel Hydro, Seriate, Italy Author

Keywords:

Mont Blanc Massif, Miage Glacier, Lake Miage, Glacial lake drainage

Abstract

Drainage of ice-marginal Miage Lake (36,000 m2; maximal depth = c. 30 m) in early September 2004 occurred in two stages. Initial rapid loss (c. 325,000 m3) over two days was due to increased outflow along the boundary between the glacier sole and the till substrate at a rate of up to 2 m3/s. This lowered the lake surface until separate ponds were isolated from the subglacial drainage route. Subsequent loss over weeks took place at slower rates by leakage through permeable till, most rapidly in the deepest (SE) basin where a sealing matrix of fines was absent. This point is identified as a site of continuous leakage at all lake stages. Lake volume and water balance considerations indicate a low turnover of lake water. The exposed lake bed revealed an extensive ice foot connecting the subaerial ice cliff to the subaqueous continuation of the right-lateral moraine. The ice foot showed evidence of buoyant calving from its surface prior to lake drainage. The lake floor largely consists of moraine ridges covered by a sandy-silt drape which thickens downslope, from centimetres under shallow water to > 1 m in lake-bottom hollows. The innermost moraine relates to the latest «Little Ice Age» and the early 20th Century fluctuations of the glacier in the eastern basin. Drainage events are unlikely to pose a hazard, and occur infrequently (and seemingly randomly) whenever marginal crevasses link the perched ice-marginal lake to the subglacial drainage network.

Downloads

Published

2024-06-25

Issue

Section

Research and review papers

Similar Articles

1-10 of 446

You may also start an advanced similarity search for this article.

Most read articles by the same author(s)

<< < 1 2 3 4 5 6 7 8 > >>