I think most people have heard of the Irish potato famine (1845-49) but until I was researching my Norwegian ancestors, I never realized there was also a potato famine in Scandinavia. The conditions during 1866 – 69 were so bad than nearly 50,000 Norwegians died.
The immigration to North America was not only for the land available there, but for life itself. Travel was expensive but was often being paid for by relatives already in North America, and during the famine, even by others living in the US. This story (warning graphic content) in an 1868 California newspaper appeals to people in California to contribute to the passages for those in Norway and Sweden.
For further reading:
http://www.emmigration.info/norwegian-immigration-to-america.htm