In the mountains of Serbia and Bosnia, some 11,000 villagers remain stranded in their homes after several weeks of heavy snow made roads all but impassable. With over 2 meters (6.5 ft) of snow on the ground, emergency helicopters have begun to airlift food supplies and evacuate villagers in need of medical care. The BBC reports that snow fell across the region almost daily since early January, with more expected over the weekend.
While the core of the arctic air has been centered over eastern Europe, few parts of the continent have escaped winter’s icy grip. In Italy, forecasters have called it the coldest week in 27 years, as widespread snow disrupted transportation across the northern and central part of the country. (AccuWeather reports heavy snow in Rome this morning) Snow even fell as far south as the Mediterranean island of Corsica, where some locations recorded over 20 cm (8 inches).
Farther north, canals have lent themselves to ice skating in the Netherlands, and in northern Germany, the Elbe River has started to freeze over.
What’s causing the extreme cold?
Occasionally, these two pressure systems weaken simultaneously, allowing a dome of cold Siberian air to drift westward into Europe and North America (bottom right image).
When arctic air plunges into the mid-latitudes for an extended period, it usually means that the Arctic Oscillation (AO) and North Atlantic Oscillations (NAO) are both in their negative phases (also illustrated to the right). Currently, however, these two patterns are not in sync: the AO is negative, but the NAO remains positive. The result is that Europe and Asia have experienced extreme cold, while most of North America has seen an unusually warm winter.
Frigid conditions are expected to remain in place into early next week, with the core of the cold parked over Western Europe this weekend. The UK Met Office is forecasting possible snow showers in the eastern UK as a low pressure system arrives from the west. In central and eastern Europe, temperatures have slowly begun to rise, but will stay below freezing, some 5-10ºC below average.
Wintry weekend forecast for the UK (UK Met Office)
Cold spell slams Europe (CNN)