Cyclone Dagmar
Cyclone Dagmar (also referred to as Cyclone Tapani in Finland) and as Cyclone Patrick by the Free University of Berlin) was a powerful European windstorm which swept over Norway on Christmas Day 2011, causing severe damage in central coastal areas, before continuing over the Scandinavian peninsula towards the Baltic Sea and Gulf of Finland. The storm caused $45 million (2011 USD) in damage.

Meteorological history
Patrick formed as a small low just south of Newfoundland on 24 December. The system raced across the north Atlantic, deepening rapidly to  by Christmas Day. Patricks extraordinary windspeed was due to it being a secondary low to the deep cyclone Oliver to the north and the powerful high Cora to the south, enhancing the southwesterly winds on the south side of the low.   On 26 December, Patrick made landfall in western Norway with a central pressure of . The storm continued to move eastwards at a rapid pace, however, as it was overland it had weakened significantly. It hit Finland the same day, St. Stephen's Day (Tapani in Finnish), and got the Finnish name due to that day. It then moved out of the Free University of Berlin's tracking charts the next day.

Impact

Norway

Patrick (Dagmar) arrived in Norway as a southwesterly storm, with windspeeds estimated to be on average  on the coast. Up to  10 minute sustained winds was measured at Kråkenes Lighthouse, Sogn og Fjordane, before the anemometer broke. Powerful winds occurred in Sogn og Fjordane, Møre og Romsdal and Trøndelag during the night of 24 December and early morning of 25 December. Extreme high storm surge in Finnmark estimated to be  over normal sea levels, although this was due to the preceding storm Cato (Oliver). In Norway comparison was made with the New Year's Day Storm of 1992, however this storm was not as strong Patrick (Dagmar) is believed to be the third strongest storm to hit Norway in 50 years. 
A large landslide on 1 January 2012 close to the Norwegian city of Trondheim has been attributed to the warm weather and large amounts of rain the system brought to the area, which resulted in 50 people being evacuated. The pier area of Trondheim was badly damaged during the storm, heavily damaging the façade of the Pirbadet water park. A F2 tornado was reported in Hellesylt, Norway. The Tanker BW Thames was disabled and adrift northwest of Bergen as the storm approached, however the crew were able to regain power and survived the storm without incident. The Russian trawler Krasnoselsk sank in Hundeidvika harbour, Sykkylven, Norway. Dagmar knocked out 390 Telenor communication masts leaving 40,000 customers without mobile or landline telephone connections. Royal Dutch Shell's Ormen Lange gas processing plant was inoperable after its electricity was cut off by the storm, which left gas supplies in the UK vulnerable as this facility can supply up to 20 percent of the UK's supply via the Langeled pipeline.

Sweden
Storm Dagmar mostly affected Southern Norrland and northern Svealand. The Swedish transport authority suspended all train traffic north of Gävle at 20:00 on Christmas Day in preparation. 
Many trees fell in the storm, bringing down power lines and blocking roads and railways. Approximately 170,000 households were left without power between Uppland and Västerbotten, some for several days. Train traffic came to a standstill in Norrland, however the principal north–south route of the country (European route E4) was quickly cleared. Several weather stations in the Norrland interior experienced their strongest wind gusts in 15 years. Winds of  were recorded on the pylons of the Höga Kusten Bridge. 1.2 million Swedish Kronor of damage was caused in Ljusdal when sixteen rail wagons weighing  were blown along the railway for  until they derailed on a road intersection. Some 40,000 homes were still without power around 14:00 on 27 December.

Finland
Patrick (Tapani) was dubbed the worst storm in Finland in 10 years. Thousands of customers were left without electricity in Southern Finland. 
The storm was a rare event in Finland and gave the warmest Christmas period in half a century. 
An old man is reported to have died after being hit by a falling tree.

Estonia
Patrick left 100,000 homes without power in Estonia, and triggered 600 rescue operations. Eesti Energia reassigned its customer services personnel to answer emergency calls. Patrick also brought record high temperatures to the country for December. Flooding was reported in the streets of major cities.

Russia
The Saint Petersburg Dam gates were closed to protect the city, preventing 15 ships from entering the port. The storm tore metal sheeting from roofs and many trees were brought down. Leningrad Nuclear Power Plant was also affected, as algae and mud stirred up by the storm were sucked into the cooling system, resulting in one of the generators being shut down.

Aftermath
Deutsche Bank estimated that the price of wood could fall by up to 15%.

See also
List of European windstorms
Cyclone Xaver
Cyclone Ulli

References

External links

   Gallery of damage in Romsdal (in Norwegian)
   Gallery of damage in Trondheim (in Norwegian)
   Air Worldwide Event Summary:Extratropical Cyclone Dagmar
  Bloomberg Business Week: Storm Dagmar Cuts Power, Causes Damage Across Nordic Region

Dagmar
2011 meteorology
2011 in Finland
2011 in Norway
2011 in Sweden
December 2011 events in Europe
2011 disasters in Europe