Select Committee on Northern Ireland Affairs Second Report


  16. We sought evidence from the Meteorological Office on the severity of the storm. This revealed that recorded mean wind speeds at stations across Northern Ireland ranged from Gale Force 8 to Violent Storm Force 11.[15] Higher wind speeds will undoubtedly have occurred in some locations. At Aldergrove, new records were set for both gust speeds and storm duration. Severe Gale Force 9 criteria were met for five consecutive hours and Gale Force 8 criteria for 10 consecutive hours.[16] This was the most severe "wind event" there, on both grounds, since records began in 1928.

  17. The storm also affected considerable areas of the Republic of Ireland, southern Scotland and northern and north western England in particular. Hurricane force mean wind speeds were recorded at Malin Head, County Donegal, and gusts of 109 mph were recorded there and 107 mph at Belmullet, County Mayo.[17] ESB,[18] the public electricity supplier in the Republic of Ireland, described the storm as "the worst to hit the north of the country for over 35 years." [19] Scottish Power reported[20] gusts in excess of 105 mph. Yorkshire Electricity, less severely affected than areas to the north, commented[21] that maximum windspeeds over the period 26 to 28 December were materially higher than had been forecast.

  18. Ine vitably, comparisons have been drawn with the severity of the Christmas Eve 1997 storm. The Meteorological Office reported that this storm was both less severe and of shorter duration, lasting some two to three hours, than the 1998 storm. [22]

  19. We also asked the Meteorological Office for its assessment of t he statistical frequency with which such storms as the Boxing Day storm could be expected in Northern Ireland. [23] On the assumption that such storms are independent events, its judgement was that, in any year, the statistical probability of such a storm recurring at Aldergrove in that year is less than one in a hundred. The Meteorological Office did stress, though, that this is a statistical average; there is no guarantee that such an event would not repeat next year. Equally, it might be 200 years, or more, before there is a recurrence. By contrast, the return period of a storm, at Aldergrove, of the intensity an d duration of the 1997 storm there is estimated to lie in the five to eight year range. [24]

  20. In view of concerns about the possible impact of global warming on the climate, we subsequently sought the views of the Meteorological Office on the possibility that such storms might become more frequent as a result of global warming. It would appear that there are natural variations in storminess around the British Isles, occurring over periods of decades to centuries, and that it is indeed possible that the greenhouse effect may influence storminess in the future, causing an increase in the incidence and severity of storms. However, little is known as to how the two factors might interact, so the extent to which historical extrapolation is relevant to predicting future trends is uncertain.[25]

15  Appendix 23, p. 104. Back

16  Appendix 23, p. 104. Back

17  Appendix 23, p. 104. Back

18  Electricity Supply Board Back

19  Appendix 19, p. 83. Back

20  Appendix 16, p.82. Back

21  Appendix 11, p. 75. Back

22  Appendix 30, p. 113. Back

23  For information on the severity of the weather conditions in Great Britain, see OFFER report, paras. 2.1 to 2.6. Back

24  Appendix 30, p. 113. It should be noted, though, that the two storms principally affected different parts of Northern Ireland: the 1997 storm had greatest effect in the south east parts of Northern Ireland. Back

25  Appendix 30, p. 114. Back

previous page contents next page

House of Commons home page Parliament home page House of Lords home page search page enquiries

© Parliamentary copyright 1999
Prepared 29 July 1999