Storm Anatol over Europe in December 1999: impacts on societal and energy infrastructure

Abstract

Abstract. Storm Anatol impacted the North Sea and northern Europe on 3–4 December 1999. It brought hurricane force winds to Denmark and northern Germany, and high winds also in Sweden and countries around the Baltic Sea. For many meteorological stations in Denmark, the wind speeds were the highest on record and the storm was ranked as a century event. The storm impacts included extensive forest damage, fatalities, hundreds of injuries, power outages, transportation interruptions, as well as storm surge flooding on the west coast of Denmark. Strongly committed to wind energy, Denmark lost 13 onshore wind turbines destroyed during the storm. An important industry insurer noted that this was a remarkably low number, considering the storm intensity and the large number of turbines (>3500) installed in the country. In 1999, offshore wind energy was just getting started in Europe, and the storm provided an important test of environmental extreme conditions impacting offshore infrastructure. This contribution takes a closer look at the regional met-ocean conditions during the storm. A brief overview is made of the wind field and available wave measurements from the North Sea. An examination is made of water level measurements from around the North Sea to characterize the storm surge and identify possible meteo-tsunamis and infragravity waves. Offshore accidents are briefly discussed to assess if there had been unusual wave strikes on shipping or platforms. At the time of the storm in 1999, there was a growing awareness in the scientific community of possible changes in ambient sea state conditions and the increasing threat of rogue waves. The offshore wind energy community had become aware from the impact of rogue waves from damage at the research platform FINO1 in the southern North Sea during severe storms in 2006, 2007, 2009, and 2013. Storm Anatol may have been another rogue wave storm at an earlier stage of offshore wind energy development.

Storm Kyrill and the storms of mid-January 2007: Societal and Energy Impacts in Europe

“…However, in the mid-2000's offshore wind energy was at the start of a growth phase, and the nature of the wave damage being encountered was a surprise (Neumann and Nolopp, 2007). The contribution follows other overview reports for Storm Anatol in December 1999, Storm Britta in November 2006, Storm Tilo in November 2007, and Storm Xaver in December 2013(Kettle, 2018, 2019, 2020, 2021.…”

“…The highest value > 35 cm was registered at the tide gauge at Bremen Grosse Weserbrücke at the mid-morning on 18 January 2007. The water level progression at this station is different from Storm Anatol in 1999 (Kettle, 2021). The gauge is located quite far up a tidal river, and the results might point to a type of resonance or tidal bore effect if instrument malfunction could be ruled out.…”

“…The potential levelling issue among the tide gauge water levels that was raised by Kettle (2021) was unresolved in the present study. The issue concerns the difference in average water level calculated directly from the 16 d data sets and the official sea level that is reported for each tide gauge.…”

“…A spectral analysis technique was used to separate the water level time series into different components corresponding to the long period (mostly storm surge), short period (mostly harbour seiche or meteo-tsunami), and tidal (diurnal plus semidiurnal, combined) contributions. The analysis follows similar tide gauge studies of Gönnert et al (2004) and Kettle (2018Kettle ( , 2019Kettle ( , 2020Kettle ( , 2021. A discrete Fourier transform was used to convert the detrended time series data into a power spectrum (Stull, 1988), similar to the example for Aberdeen in Fig.…”

“…Water level data from tide gauges around the North Sea are analysed to trace the progress of the storm surge and to investigate the short period component of water level variation that may be linked with meteo-tsunamis or infragravity waves. The same procedure was followed as in the previous storm investigations of Kettle (2018Kettle ( , 2019Kettle ( , 2020Kettle ( , 2021 with minor modifications. For the North Sea, water level variations are dominated by the tidal component.…”