Weather conditions in northern Europe in the exceptionally cold spring season of the Famine Year 1867. Geophysica

In 1867, the mean May temperature over large areas of Northern Europe was so low that anomalies of that magnitude can be expected to occur only a few times in a millennium. Cold weather conditions continued for the first half of June. On the basis of the available observational data, we re-constructed the temperature anomaly and surface pressure patterns over Europe for both months, and compared these with the distributions of other meteorological parameters. The daily synoptic situations in Northern Europe were also analyzed. The extreme coldness of May was caused by a quasi-stationary flow pattern with high surface pressure over the Norwegian Sea and a depression over Northern Russia, bringing cold air into Northern Europe from the north and north-east. An anomalously extensive ice cover in the Arctic Ocean also contributed to the coldness. The northerly stream was sporadically strengthened by transient cyclones that travelled over Southern Scandinavia, the Baltic area or Central Russia to the east and north. The associated cold surges produced below-zero day-time temperatures at 60ºN even in mid-May. In the first half of June, several cyclones passed over Central Scandinavia, filling over Finland and Northern Russia. The cold air stream continued to prevail, especially in Northern Scandinavia. An abrupt change in the weather type occurred around 20 June, when a warm easterly airstream spread into Northern Europe, and temperatures rose suddenly by about ten degrees. Key words: Spring 1867, famine year, northern Europe 1