Gudrun was a powerful storm which hit Denmark and Sweden on 8 January 2005, and Latvia and Estonia on 9 January 2005. The name Erwin was chosen by the Free University of Berlin, while the storm was named Gudrun by the Norwegian Meteorological Institute and was the name used in Sweden. Sustained wind speeds of with wind gusts of were measured in Hanstholm, Denmark – the same strength as a Category 1 hurricane.

The storm caused significant financial damage in Sweden, where the forest industry suffered greatly from damaged trees, as more than of trees were blown down in southern Sweden. This resulted in Sweden at the time having the world's largest surplus of lumber.

About 415,000 homes lost power in Sweden and several thousand of these were without power for many days and even weeks in some cases, as about 10,000 homes were still without power after three weeks. The death toll in Sweden was nine victims, eleven in the clearing work, making it one of the biggest environmental disasters in Swedish history, while four were killed in Denmark and one in Estonia.

Meteorological history

thumb|Fallen tree by [[Onslunda|Onslunda Church in Sweden]]

On 6 January 2005, a low pressure system developed at a frontal zone south of Newfoundland. It moved into the central North Atlantic and was named 'Erwin' by the Free University of Berlin.

Sweden blackout and damage to forests

Gudrun is one of the strongest storms to impact Sweden in the last 100 years. It caused much damage to forests in Halland the southwestern part of the South Swedish highlands (Småland). Spruces were particularly hit by Gudrun, while other trees with a more steady root system fared better.

Political impact in Sweden

In her dissertation, "Natural Disasters and National Election", Lina M. Eriksson, found that the storm played a crucial role in the historic regime shift in the 2006 Swedish general election. The incumbent Social Democratic Party's poor crisis response to Gudrun, hitherto the most expensive natural disaster in Swedish history, significantly contributed to the incumbent's loss. In a subsequent article in Electoral Studies, it was observed that the deficient storm response still swayed voters in the 2010 and 2014 elections.