Case study of a tornado in the Upper Rhine valley

Abstract

On 9 September 1995 a short-lived tornado occurred in the Upper Rhine valley near Oberkirch-Nußbach, uprooting several trees as well as damaging buildings and cars. The storm, confirmed by eye witnesses and damage analyses performed by Wetteramt Freiburg of the German Weather Service, was also detected by the IMK C-band Doppler radar in Karlsruhe. The data show a well-defined mesocyclonic rotation in the tornado's parent Cb cloud. The orography distinctly influenced the development of a wind field suitable for supercell formation. This points to preferred areas of tornadic activity. The dominant effects of vertical wind shear compared to convective energy during tornado genesis are evident for this storm. Its small scale confirms the existence of small supercell storms being studied in the USA in recent years.

Keywords

• upper rhine valley
• germany
• tornado
• orography
• supercell formation
• mesocyclonic rotation
• mesozyklone
• superzellen-gewitter