On Thursday 8th December 2011 an intense Atlantic low-pressure system brought widespread storms to central Scotland. Wind speeds recorded by the ECN Cairngorms weather station that has been operating since 1999 were the highest ever recorded there.
Wind speeds grew gradually throughout the day (figure 1), starting from near the average December wind speed of 18mph, to a peak of 80mph (hourly average speed) between 13:00 and 14:00; replacing the previous maximum recorded speed of 69mph set on the 12th January 2005. Gusts during the peak of the storm were recorded at speeds as high as 112mph.
Temperatures were not particularly cold for the time of year, just below freezing and only slightly below the December average (0.58°C), but with the wind chill factor, it would have felt considerably colder.
Figure 1: Hourly average wind speed recorded by the ECN Cairngorms weather station during 8 December 2011
At higher altitudes nearby the wind was even stronger, with speeds as high as 165mph being reported by the UK Meteorological Office for the weather station on Cairngorm summit (12km east and 545m higher at 1245m above sea level). This is the equivalent of a category 5 hurricane. Fortunately the 8th December was not a routine ECN sampling day! No ECN equipment was damaged by the winds.
The Cairngorms site is extremely exposed and windy but the conditions on 8 December were certainly exceptional, as the graph in figure 2 illustrates. Strong winds play a dominant role in shaping the short-clipped and lichen-dominated vegetation at the site. Recent research1 has investigated how changes in wind speed in the longer-term might influence the response of vegetation to climate warming in the region. The authors concluded that changes in wind speed need to be incorporated into models of species response to warming.
Figure 2: Annual average wind speeds recorded at the ECN monitoring site in the Cairngorms (the figure for 2011 is calculated on available data)
- ECN Cairngorms
- Met Office news release concerning the storm
- 1Crabtree, D. and Ellis, C. J. (2010), Species interaction and response to wind speed alter the impact of projected temperature change in a montane ecosystem. Journal of Vegetation Science, 21: 744–760. doi: 10.1111/j.1654-1103.2010.01184.x