There is a lot of cross-border information on storms in Northern, Western and Central Europe. This information is summarized on the page for Europe in the window 'Storms: European scale'.
Vulnerabilities – Coastal erosion
Estonia has a long (3,800 km) coastline due to numerous peninsulas, bays and islands (over 1,500). Owing to its flat and low-lying coastal zone, which is experiencing isostatic and tectonic uplift, the development of the coast should be stable, although activation of coastal processes has been observed in Estonia for the last 20-30 years. Researchers relate the extensive erosion and alteration of depositional coasts, such as sandy beaches, to the recent increased storminess in the eastern Baltic Sea (1).
Storm data were related to the most significant recorded coastal change events. According to the researchers, the most marked coastal changes in Estonia result from a combination of strong storms, high sea-levels induced by storm surge, ice free seas and unfrozen sediments, all of which enhance erosion and transport of sediments above the mean sea-level and inland the mean coastline (1).
Frequency of storm days varied greatly during the second half of the 20th century with a minimum in the 1960s and a maximum during the last two decades. The increase during the last two decades is probably associated with increased westerly’s and cyclonic activity in Northern Atlantic in winter resulting in warmer winters in northern Europe and an ice-free Baltic Sea near the Estonian coast (1).
Vulnerabilities – The impact of the storm Gudrun
The storm Gudrun hit Scandinavia and the Baltic States on 7-9 January 2005. It was one of the worst storms in this region in the last 40 years. There was massive forest damage. 17 people were killed (including Ireland and UK) (2). The storm took its toll even after it had passed. According to the Swedish Meteorological and Hydrological Institute, 20 people were left dead after the storm while conducting dangerous tasks related to the damages it caused (3).
The winter storms hitting northern Europe form on the so-called polar front. This is a wide belt between 50 and 60 degrees latitude, where cold polar air and southern air masses warmed by the oceans meet. This is the reason behind the quite variable weather normally experienced in the countries bordering the Baltic Sea. During the polar winter, as the high latitudes receive hardly any solar radiation and the southern air masses are still heated by both the solar energy and the warmth stored by the oceans, the difference in temperatures between these two air masses becomes large enough to trigger the storms.
The storm Gudrun traversed over the Scottish highlands, Southern Norway and Sweden, reaching the Finnish coast a couple of hundred kilometres south of Kokkola. It then continued towards Russian Karelia, already considerably weakened (4). The highest wind speed was measured in Denmark and Estonia.
Total damage caused by the storm would be roughly 1 billion EUR in Nordic and Baltic countries alone (5). Swiss Re calculated the insured losses alone to reach 1.5 billion EUR (1.9 billion USD) (6). It has to be noted, that the share of nonlife insurance policies is far bigger in the Western Europe than it is in the Central and Eastern Europe.
Remarkable feature of the storm were the vast power cuts, that for example in Latvia cut some 60 per cent of the country’s population from power. In Denmark and in particular in Sweden the storm caused huge forest losses, with damages totaling some 230 million EUR in Sweden alone. Germany and Poland luckily escaped without major damages, although excessive coastal erosion was reported in places in both countries.
The main effects of the storm on natural systems can be divided in three categories:
- Forest losses and partly related power cuts, especially in Sweden and Denmark but also in the Baltic countries;
- Accelerated coastal processes, namely coastal erosion, in Latvia, Lithuania and Estonia, but also in Poland and Germany; through risen water level and heavy wave action during an ice-free period;
- Coastal flooding in Estonia, Finland and Lithuania, extending to Russia; as a result of a storm surge pushed by the storm front.
Gudrun did not reach the impacts of the fiercest winter storms of past years, namely Lothar and Martin of 1999 and Jeanett of 2002. The two storms of December 1999 still are the most expensive storms recorded, together totaling over 12 billion EUR in insured damages. 125 people were killed and nearly four million affected. Forest losses were massive in Southern Europe (7). Based on studies made by the insurance company Swiss Re, storms like these have a return period of only ten years, however (7). Damages worth over 1 billion EUR occur every two or three years, as in case of Jeanett in 2002. In the area affected they were exceptional, however (7).
Vulnerabilities – Gudrun and forest losses
The number of storm damages to European forests has been on the rise (8). The example of Gudrun shows some of the many factors contributing to this:
- The area of forest altogether is on the rise again because of agricultural land lost to forestry.
- Planted monocultures are more common, with especially spruce forests being vulnerable to storms – partly because of their root structure, partly due to being evergreen plants with large foliage to take the power of winter storms.
- Rougher harvesting techniques increase root damages and the effect of wind on the forest plots. Trees are also planted on soils not totally suitable for them. Modern means of forestry leaves northern European forests vulnerable to storm damages.
- The key reasons for forest damages in the future too are natural conditions, especially the relapse period of extreme storm events.
Although the fallen trees are the most visible reminder of the cost of a storm event, harvesting the fallen timber is only the starting point of storm damages. Apart from the unavoidable cost of clearing up and replanting the forests felled by storm winds, many cumulative factors increase the cost of replanting:
- The felled areas have to be surveyed.
- To avoid insect damages, the trees should be harvested as soon as possible, preferably before the summer. This adds to the cost of normal harvesting.
- The excess amount of dry timber in the forest increases risk of forest fires.
- Large amounts of timber on the market, although of poor quality, decrease the timber price per cubic meter.
- On top of this, the growing cycle has to be started anew, and it takes decades before the trees reach their prime growing age again.
Vulnerabilities – Gudrun and coastal erosion
In the case of the storm Gudrun, the combination of lack of sea ice, unusually high sea levels and the intensive storm surge created perfect conditions for the wave action to hit the coastal areas at full force (3).
The high sea level enabled for the energy of the waves to hit coastal stretches even beyond their landward boundaries (9). Reduced sediment discharge of many European rivers because of abstraction of waters increases the coasts’ vulnerability to the impacts of climate change. It is seen, that 90% of sediment discharge should come from river basins (10). Developments of river dams and abstraction of water is to blame, also in Europe, where almost all main rivers are dammed (10). In the Gulf of Riga also dredging of sand from the rivers for construction purposes has increased coastal erosion.
In the sandy south coasts of the Baltic Sea extensive erosion was the main concern. On these coasts, extreme weather events have been found being main erosive agents. Their strength is enhanced with the lengthening of the ice-free period. It has also been seen that the number of strong storms is on the rise. Lithuania for example has experienced 10 storms previously considered as ‘once in a hundred years events’ during the past 50 years! (3).
Vulnerabilities – Gudrun and flooding
Gudrun caused floods in Denmark, Estonia, Finland, Lithuania, Poland and Sweden.Although the water level was record high in Helsinki, severe damages were avoided. The flood threatened the historical centre however and in many places the water rose to built areas. It also caused potential disaster situations in the ever increasing underground spaces of the city, such as the multi-utility and metro tunnels (11).
All outlet pipes of the sewage system in Helsinki had to be manually blocked in order to keep the sea water from flowing into the system. A water treatment plant in which all waste water handling in Helsinki is concentrated was flooded, forcing the officials to release some 63,000 m3 of sewage water untreated to the sea. In Finland, the cost to both public and private sectors adds up to a total of 1.5 billion EUR. Damages were mainly related to the seawater flowing to cellars and harm done to summer houses.
In Pärnu (Estonia) the storm resulted in the highest storm surge ever recorded. It was the worst natural disasters for Estonia in terms of property damage due to storm wind and flooding. The maximum coastline recession reached about 1 km in Pärnu, flooding densely populated urban areas (12).
Sea level reached a relatively modest 230 cm in St. Petersburg on 9 January. Along the Swedish coast of the Baltic Sea, Gudrun produced negative surges with relative sea level drop up to 150 cm.
Vulnerabilities – Gudrun and total damage
The European Commission estimated the total damage in Southern Sweden to be 2.3 billion EUR, making it the country’s worst natural disaster in modern time (13). This adds up to nearly 0.8% of Sweden’s GDP. In Lithuania, total damages were estimated by the EU to be approximately 15 mio EUR (slightly over 0.07% of GDP). In Latvia, the damage was put at 192 mio EUR (1,5% of GDP), Estonia’s share was 1.3 mio EUR and GDP of 0,46%. For comparison, the cost of the storm in Finland was about 20 mio EUR, 0,01% of the GDP in 2005 (14).
Gudrun exposed the lack of adaptation towards weather borne hazards that already today pose a threat to the countries bordering the Baltic Sea. Climate change is expected to enhance extreme weather events that are thus likely to occur at a shorter interval in the future (3).
Vulnerabilities – Gudrun and energy production
In Denmark, that first experienced the effects of the storm, the struggle started towards the afternoon of January 8th. Main worry seems to have been the faith of the country’s wind energy production and whether the some 5400 wind turbines in Denmark would stand the storm (3).
As wind speed rose above 25 m/s on a broad front in whole of western Denmark, most of the circa 4000 turbines operated by the local electricity provider Eltra automatically shut down. This reduced the amount of energy produced locally to less than 1/20 of the full capacity of total 2,380 MW. This power demand was filled with regulating power bought abroad – but not without difficulties, as the storm started to affect energy production on a wide area in Northern Europe (15).
The single most notable event was forced closing down of four nuclear reactors and considerable downscaling of fifth in Sweden (16). The Finnish nuclear units at Loviisa encountered problems as well. Although not really threatening events, the examples of Sweden, Finland and Denmark can be seen as signs of the problems of unilateral energy production. In a case of extreme weather event, as normal means of energy production fail, acquiring the capacity needed from abroad may be hard, as was seen in Denmark.
The effects were very severe in Latvia. 54,000 km of distribution lines were damaged, leading to a 23 day long emergency situation. The main reason for this were trees fallen on lines, but 3 transmission line towers collapsed and 34 were damaged, too. What resulted was ‚the largest mobilisation ever in the Latvian electricity business. Some 6000 people worked on clearance and repairing activities.The power cutoffs influenced some 60 % of the territory of Latvia, and approximately 400,000 (about 40 %) electricity customers were left without electricity in the immediate aftermath of the storm.
About 100,000 households had power cuts in Denmark and Estonia. About 30,000 km of power lines were damaged in Sweden. In Lithuania about 230,000 residents were temporarily left without electricity. In many analyzed countries the communications cuts were observed.
The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Estonia.
- Orviku et al. (2003)
- Guy Carpenter (2005), in: Haanpää et al. (2007)
- Haanpää et al. (2007)
- Suursaar et. al. (2006a)
- Guy Carpenter (2006), in: Haanpää et al. (2007)
- Swiss Re (2006), in: Haanpää et al. (2007)
- European Environment Agency (EEA) (2003)
- UN (2004), in: Haanpää et al. (2007)
- Kont et. al. (2007)
- Meiner (2006), in: Haanpää et al. (2007)
- Lilja (2005), in: Haanpää et al. (2007)
- Suursaar et al. (2006b)
- European Commission (2006a), in: Haanpää et al. (2007)
- Eurostat (2005), in: Haanpää et al. (2007)
- Andersen (2006), in: Haanpää et al. (2007)
- WNA (2005), in: Haanpää et al. (2007)