Tornado and Storm Research Organisation, Oxford Brookes University, Oxford - U.K.
This paper reports the incidence of waterspouts/tornadoes along the English South Coast with special attention to areas north and east of the Isle of Wight where the frequency proved to be surprisingly high. Resulting property damage can be severe, leading to intensities deduced from the International Tornado Scale as high as T8. Furthermore, the widest tornado track of the last 15 years was 900 metres broad (this was a T3 event which went through the town of Selsey in Sussex in January 1998). Several tracks have been a few kilometres in length. On extreme occasions (14 December 1810, 28 September 1876, 7-8 January 1998, 28 October 2000, 30 October 2000) many dozens, and sometimes several hundreds, of properties were damaged. The risk to shipping is clearly very high, especially as some of these dangerous events took place at night.
The synoptic conditions for several case studies have been analysed, from which we find that most vortices formed on active fronts and in shear-zone situations including coastal fronts. We conclude that the presence of the land mass of the Isle of Wight introduces a lee effect which triggers vortex formation in marginal cases or intensifies vortices in others. Regions to the lee of headlands and peninsulas may also have a higher incidence of waterspouts and tornadoes than would otherwise be expected.