Recorded presentation6.6
The 1962 severe Windstorm in Yorkshire, England
Ralph Burton, University of Leeds, Leeds, United Kingdom; and S. D. Mobbs
In February 1962, severe gales devastated parts of Sheffield, England, killing three people and damaging over a hundred thousand buildings; maximum gusts of 42m/s were recorded during an 8-hour period of intense winds. Observations showed that the windstorm took the form of a narrow band of high winds, in the lee of the Pennines (a moderately high ridge, running approximately 400km long in a north-south direction, with maximum elevations in the region of 900m above sea level) and under the influence of a prevailing north-westerly flow. Interestingly, regions of Yorkshire close to Sheffield did not experience such devastating effects.
Only 5 days prior to this major event, Sheffield had experienced another, similar, severe windstorm; although the only other comparable events happened 5 years and 60 years previously, suggesting that the return time for such a storm is rather high, and that the conditions necessary for its occurrence are not common.
A previous study (Aanensen and Sawyer, Nature, Feb. 1963), published soon after the event and making use of two-dimensional linear theory, suggested that the damage was caused by Sheffield being located underneath the trough of a lee wave. For the present study, results from the Weather Research and Forecasting (WRF) model will be presented. Initialised with ERA-40 re-analyses, the model has been run in nested mode with high resolution (1km) over the north of England. The complex, three-dimensional nature of the lee-wave windstorm was reproduced, and results will be shown for Sheffield and surrounding areas, and the mechanism of generation will be investigated. The severe damage attributed to this storm will be shown to be due not only to high mean winds, but to transient, rotor-like features, causing the very localised nature of the damaging effects of the wind storm.
An important aspect of this work, giving it operational as well as historical and scientific interest, is whether the synoptic situation leading to the gales would be interpreted by the latest models as being conducive to the generation of such a windstorm - the return times suggesting that another such event could well occur in the future.
Session 6, Foehn, Boras, and Windstorms
Tuesday, 31 August 2010, 10:30 AM-12:00 PM, Alpine Ballroom A
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