In Norse mythology, Fimbulvetr (or fimbulvinter), commonly rendered in English as Fimbulwinter, is the immediate prelude to the events of Ragnarök.
Fimbulvetr is the harsh winter that precedes the end of the world and puts an end to all life on Earth. Fimbulwinter is three successive winters where snow comes in from all directions, without any intervening summer. During this time, there will be innumerable wars and ties of blood will no longer be respected: the next-of-kin will lie together and brothers will kill brothers.
The event is described primarily in the Poetic Edda. In the poem Vafþrúðnismál, Odin poses the question to Vafþrúðnir as to who of mankind will survive the Fimbulwinter. Vafþrúðnir responds that Líf and Lífþrasir will survive and that they will live in the forest of Hoddmímis holt.
This mythology might be related to the extreme weather events of 535–536 which resulted in a notable drop in temperature across northern Europe. There have also been several popular ideas about whether or not this particular piece of mythology has a connection to the climate change that occurred in the Nordic countries at the end of the Nordic Bronze Age dating from about 650 BC. Before this climate change, the Nordic countries were considerably warmer.
In Denmark, Norway, Sweden and other Nordic countries, the term fimbulvinter is still used to refer to an unusually cold and harsh winter.
Fimbulvetr comes from Old Norse, meaning "awful, great winter". The prefix "fimbul" means "the great/big" so the correct interpretation of the word is "the great winter".
See also 
Other sources 
- Gunn, Joel (2000). The Years Without Summer: Tracing A.D. 536 and its Aftermath (British Archaeological Reports International. Oxford, England: Archaeopress) ISBN 1-84171-074-1
- Lindow, John (2001). Norse Mythology: A Guide to the Gods, Heroes, Rituals, and Beliefs (Oxford University Press) ISBN 0-19-515382-0
- Larrington, Carolyne (Trans.) (1999). The Poetic Edda (Oxford World's Classics) ISBN 0-19-283946-2
- Keys, David Patrick (2000). Catastrophe: An Investigation into the Origins of the Modern World. (New York: Ballantine Pub) ISBN 0-345-40876-4.
- Orchard, Andy (1997). Dictionary of Norse Myth and Legend (Cassell) ISBN 0-304-34520-2