Once upon a time, winters were synonymous with meters of snow, frozen rivers and children spending whole days on sleds. Snow cover was a matter of course, not an exception, a white Christmas was one of the traditions that no one paid attention to.
Today, however, the sight of snow-covered streets is more of a pleasant surprise than a certainty. Winters seem to have lost their typical face, and the snow that once complicated traffic and life is slowly turning into a rare phenomenon that is talked about with nostalgia. Why is that so? The website explained the reasons.
It’s not just a feeling, meteorological measurements also confirm it. The weather is influenced by several factors, including global warming, warmer oceans and more frequent inflow of mild air, changes in atmospheric circulation or local influences and landscape change.
Scientists warn that Earth’s average temperature has increased by about 1.2 to 1.4°C since the pre-Industrial Revolution. Europe is warming faster than the global average. Winter is the season when people are most aware of global warming. Even a small increase in temperature can cause fundamental changes. A difference of 1 or 2 °C often decides whether precipitation falls in the form of snow or rain.
The weather is also influenced by the oceans, which accumulate a huge amount of heat. Compared to the past, the Atlantic Ocean has been noticeably warmer in recent years and releases a large amount of energy into the atmosphere even during the winter. Therefore, warm and humid oceanic air reaches Europe more and more often, which causes a milder course of winter, especially in the central part of the continent.
This phenomenon is most pronounced in Western and Central Europe (Slovakia), where the westerly to southwestern flow dominates. Cold and dry air from the east gives way to frequent pressure lows, which bring with them rain, stronger winds and temperatures above zero.
In the past, winters were often influenced by strong pressure highs that got “stuck” over northeastern Europe or Russia. It acted as an imaginary barrier, opening the door to very cold, dry air from the north and east. It then flowed into Europe for weeks, bringing severe frost and snow. Today, such stable situations appear much less often or last only a short time, so the cold does not have time to persist.
The so-called polar vortex also plays an important role. This is a region of very cold air located high above the North Pole. When it is strong and stable, it holds the frost in the north. When it breaks, the cold is “spilled” to lower latitudes. In recent years, although the polar vortex has broken more often, the cold air mostly goes to North America or Asia. So Europe often stays in an area where warmer air flows, and our winters are milder than we remember from the past.
The most significant loss of snow is noticeable in lower positions. If a snowpack does fall, it usually lasts for a very short time. More and more often, we encounter situations when snowfall quickly turns into rain or is immediately replaced by warming.
In the mountains, the situation is different. Although it snows in these places and even sometimes more intensively than in the past, the snow season tends to be shorter. The snow line is moving higher and the rain is also affecting mountain areas where permafrost once prevailed.
Local conditions also contribute to the fact that winters look different today than they used to. Cities in particular act as so-called heat islands. These are buildings, roads and concrete that heat up during the day and then maintain the heat at night. As a result, it is several degrees warmer in the city than in the surrounding nature, the snow either does not stay there at all, or disappears very quickly.
How the landscape changes also plays its role. Forests, wetlands and places that can retain water in the soil are decreasing. When there is a lack of moisture and greenery, the land overheats faster and the snow melts much earlier than in the past. Thus, winter loses its typical white appearance even outside the big cities.
