Articles | Volume 6, issue 5
Nat. Hazards Earth Syst. Sci., 6, 861–879, 2006
Nat. Hazards Earth Syst. Sci., 6, 861–879, 2006

  06 Oct 2006

06 Oct 2006

The disastrous storm of 4 November 1966 on Italy

S. De Zolt1, P. Lionello2, A. Nuhu3, and A. Tomasin4 S. De Zolt et al.
  • 1Department of Physics, University of Padua, via Marzolo 8, 35131 Padua, Italy
  • 2Department of Materials Science, University of Lecce, via Arnesano, 70300 Lecce, Italy
  • 3Department of Physics, University of Padua, via Marzolo 8, 35131 Padua, Italy
  • 4Department of Applied Mathematics, University "Ca' Foscari" and ISMAR-CNR, San Polo 1364, 30125 Venice, Italy

Abstract. This is the first modeling reconstruction of the whole aspects (both meteorological and oceanographic) of the storm which hit Italy on 4 November 1966, producing 118 victims and widespread damages in Tuscany, at the northern Adriatic coast and in the north-eastern Italian Alps. The storm was produced by a cyclone which formed in the western Mediterranean and moved eastward towards Italy, reaching the Thyrrenian Sea, and then northward. The most peculiar characteristic of the storm has been the strong zonal pressure gradient and the consequent intensity and long fetch of the south-easterly sirocco wind, which advected a large amount of warm moist air, and determined exceptional orographic precipitation over Tuscany and the north-eastern Alps. The funneling of the wind between the mountain chains surrounding the Adriatic basin further increased the wind speed and determined the highest ever recorded storm surge along the Venetian coast.

This study shows that present models would be able to produce a reasonably accurate simulation of the meteorological event (surface pressure, wind and precipitation fields, and storm surge level). The exceptional intensity of the event is not suggested by single parameters such as the sea level pressure minimum, the wind speed or the total accumulated precipitation. In fact, the precipitation was extreme only in some locations and the pressure minimum was not particularly deep. Moreover, the prediction of the damages produced by the river run-off and landslides would have required other informations concerning soil condition, snow coverage, and storage of water reservoirs before the event. This indicates that an integrated approach is required for assessing the probability of such damages both on a weather forecast and on a climate change perspective.