Title WeMOI and NAOi influence on major avalanche activity in the eastern Pyrenees
Author García-Sellés, C.; Peña, J.C.; Marti, G.; Oller, P.; Martínez, P.
Author Affil García-Sellés, C., Geological Institute of Catalonia, Barcelona, Spain. Other: Meteorological Service of Catalonia, Spain
Source Cold Regions Science and Technology, 64(2), p.137-145, ; International snow science workshop 2009, Davos, Switzerland, Sept. 27-Oct. 2, 2009, edited by J. Schweizer. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0165-232X
Publication Date Nov. 2010
Notes In English. Based on Publisher- supplied data GeoRef Acc. No: 309825
Index Terms atmospheric circulation; avalanche forecasting; avalanches; climate; mass movements (geology); meteorology; snow; Pyrenees; Spain; Europe; Iberian Peninsula; mass movements; North Atlantic Oscillation; precipitation; Southern Europe; Western Mediterranean Oscillation
Abstract Major avalanche episodes registered in the Eastern Pyrenees (north-eastern Iberian Peninsula) are correlated with both the North Atlantic Oscillation (NAO) and the Western Mediterranean Oscillation (WeMO). The NAO is one of the most important and recurrent patterns of atmospheric circulation variability in the Northern Hemisphere and affects the behaviour of surface temperatures and precipitation in Western Europe. The Western Mediterranean Oscillation index (WeMOi) controls intense precipitation in the eastern part of the Iberian Peninsula. The link between both indices and major avalanche activity is undertaken by applying a cumulative index. A link between avalanche activity and the NAO has been found in Iceland, but it has not been detected in areas closer to the Pyrenees, such as the French Alps. This paper examines the linkage to the NAO in an area further from the centres of the dipole than is the case for Iceland. Results show a significant negative correlation between major avalanche activity in the Eastern Pyrenees and both NAO index (NAOi) and WeMOi, which is even higher with the cumulative NAOi (CNI) and the cumulative WeMOi (CWI). The cumulative index reflects the cumulative effect of snow accumulation in the avalanche starting zones as precipitation is affected by the variations of NAOi and WeMOi. Consequently, the correlation is negative since it has been demonstrated that increased precipitation in the Eastern Pyrenees is linked to negative values of both low frequency patterns. Nevertheless, results from the diverse avalanche forecasting regions in the Eastern Pyrenees suggest a different response of avalanche activity to both indices, confirming the Pyrenees as a complex snow-climate boundary. Lastly, possible changes in avalanche activity in the coming decades may be suggested by the NAO evolution associated with global warming scenarios that are foreseen and the present interannual trend of the WeMOi.
URL http://hdl.handle.net/10.1016/j.coldregions.2010.08.003
Publication Type conference paper or compendium article
Record ID 65006940