A research analyses the heavy snowfall occurred in Catalonia in 2010
A research carried out by researchers from the UB and the Meteorological Service of Catalonia (SMC) analyses 2010 heave snowfall, one of the heaviest happened last decades, if we consider its large extension as well as its local intensity and the disruption it produced. One of the main conclusions of the research is that, unlike summer thunderstorms, geographical Distribution of cloud-to-ground flashes is not necessarily related to precipitation maxima.
A heavy snowfall took place on 8th March 2010. Snow accumulations collapsed the regional communication transport network and the border with France was closed several hours. The snowfall was accompanied by lightning, which is a relatively uncommon phenomenon. The combination of lightning and snow, so-called thundersnow, is a really interesting phenomenon because, as Joan Bech, UB researcher, explains, “the number of articles in the scientific literature related to thundersnow is relatively scarce. Studying it can be useful in order to understand its differences from common summer storms, particularly those related to electrical charge distribution in thunderclouds”.
In most storms, lightning takes place in precipitation maxima areas. However, the research, affirms Nicolau Pineda, researcher from SMC, “proves that during the event a great number of thunders happened out of these areas; the research points out that they were induced by tall telecommunication towers”.
A detailed analysis of meteorological conditions obtained from weather radars and the Lightning Mapping System (XDDE) of SMC enabled to detect intracloud and cloud-to-ground lightning discharges. Nearly a third part of detected discharges are concentrated in the vicinity of tall telecommunication towers, such as Collserola telecommunication tower, in Barcelona, located at 447 m height; Puig Neulós tower, on the France-Spain border, at 1,261 m, and Rocacorba tower, near Girona, at 991 m.
“Induction is due to the low altitude in which winter storms take place; the proximity of the cloud charge to ground and the relatively large horizontal extent of that charge observed in winter thunderstorms favours the tall tower lightning triggering effect”, concludes Pineda. This hypothesis would explain the fact that electrical discharge areas are unrelated to convection ones, where precipitation maxima occurs.
Moreover, precipitation amounts in 24 h exceeded 100 mm and snow depths over low altitude terrain, where snow is rare, surpassed 30 cm. According to Bech, “snowfall was highly triggered by the burst of an upper level cold trough −30 °C at about 5,500 m), which favoured a rapid cyclogenesis over the Mediterranean”.
Furthermore, “the abundance of wet snow, combined with winds, favoured snow accumulation on wires and branches”, says the researcher. Consequently, damage was caused over large forest areas estimated in more than 20 million euros. The high voltage power line distribution grid was also affected, particularly in North-East Catalonia where 33 high power electrical towers were knocked down.
The study, published on the journal Atmospheric Research on April 2013 issue, is the result of the collaboration established between the Meteorological Service of Catalonia, which is part of the Department of Territory and Sustainability of the Government of Catalonia, and the Department of Astronomy and Meteorology at the Faculty of Physics of the UB —affiliated centre with the campus of international excellence BKC—. The research has been developed by the researchers Joan Bech, from the UB, and Nicolau Pineda, Tomeu Rigo and Montserrat Aran, from SMC.
J. Bech, N. Pineda, T. Rigo i M. Aran. "Remote sensing analysis of a Mediterranean thundersnow and low-altitude heavy snowfall event". Atmospheric Research, April 2013.Doi :10.1016/j.atmosres.2012.06.021
A research carried out by researchers from the UB and the Meteorological Service of Catalonia (SMC) analyses 2010 heave snowfall, one of the heaviest happened last decades, if we consider its large extension as well as its local intensity and the disruption it produced. One of the main conclusions of the research is that, unlike summer thunderstorms, geographical Distribution of cloud-to-ground flashes is not necessarily related to precipitation maxima.
A heavy snowfall took place on 8th March 2010. Snow accumulations collapsed the regional communication transport network and the border with France was closed several hours. The snowfall was accompanied by lightning, which is a relatively uncommon phenomenon. The combination of lightning and snow, so-called thundersnow, is a really interesting phenomenon because, as Joan Bech, UB researcher, explains, “the number of articles in the scientific literature related to thundersnow is relatively scarce. Studying it can be useful in order to understand its differences from common summer storms, particularly those related to electrical charge distribution in thunderclouds”.
In most storms, lightning takes place in precipitation maxima areas. However, the research, affirms Nicolau Pineda, researcher from SMC, “proves that during the event a great number of thunders happened out of these areas; the research points out that they were induced by tall telecommunication towers”.
A detailed analysis of meteorological conditions obtained from weather radars and the Lightning Mapping System (XDDE) of SMC enabled to detect intracloud and cloud-to-ground lightning discharges. Nearly a third part of detected discharges are concentrated in the vicinity of tall telecommunication towers, such as Collserola telecommunication tower, in Barcelona, located at 447 m height; Puig Neulós tower, on the France-Spain border, at 1,261 m, and Rocacorba tower, near Girona, at 991 m.
“Induction is due to the low altitude in which winter storms take place; the proximity of the cloud charge to ground and the relatively large horizontal extent of that charge observed in winter thunderstorms favours the tall tower lightning triggering effect”, concludes Pineda. This hypothesis would explain the fact that electrical discharge areas are unrelated to convection ones, where precipitation maxima occurs.
Moreover, precipitation amounts in 24 h exceeded 100 mm and snow depths over low altitude terrain, where snow is rare, surpassed 30 cm. According to Bech, “snowfall was highly triggered by the burst of an upper level cold trough −30 °C at about 5,500 m), which favoured a rapid cyclogenesis over the Mediterranean”.
Furthermore, “the abundance of wet snow, combined with winds, favoured snow accumulation on wires and branches”, says the researcher. Consequently, damage was caused over large forest areas estimated in more than 20 million euros. The high voltage power line distribution grid was also affected, particularly in North-East Catalonia where 33 high power electrical towers were knocked down.
The study, published on the journal Atmospheric Research on April 2013 issue, is the result of the collaboration established between the Meteorological Service of Catalonia, which is part of the Department of Territory and Sustainability of the Government of Catalonia, and the Department of Astronomy and Meteorology at the Faculty of Physics of the UB —affiliated centre with the campus of international excellence BKC—. The research has been developed by the researchers Joan Bech, from the UB, and Nicolau Pineda, Tomeu Rigo and Montserrat Aran, from SMC.
J. Bech, N. Pineda, T. Rigo i M. Aran. "Remote sensing analysis of a Mediterranean thundersnow and low-altitude heavy snowfall event". Atmospheric Research, April 2013.Doi :10.1016/j.atmosres.2012.06.021