The summer of 1866 was extremely rainy, and staple crops failed widely: potatoes and root vegetables rotted in the fields, and conditions for sowing grain in the autumn were unfavourable.
After a promisingly warm midsummer, freezing temperatures in early September ravaged crops; as a result, the harvest was about half the average.
There was no money readily available to import food from largely monopolized Central European markets, and the government was slow to recognize the severity of the situation.
Finance minister Johan Vilhelm Snellman, in particular, did not want to borrow, lest Finland's recently introduced currency, the Finnish markka, be weakened because of high interest rates.
When money was finally borrowed from the Rothschild bank of Frankfurt in late 1867, the crisis was already full blown, and grain prices had risen in Europe.
A number of emergency public works projects were set up, foremost among them the construction of the railway line from Riihimäki to Saint Petersburg.