Weather phenomenon in Germany: Ice on bodies of water just doesn’t melt

Berlin – There are still areas of ice on many bodies of water in Germany. On the Baltic Sea, the ice piles up meters high. Scenes on Rügen are more reminiscent of pack ice in the Arctic Circle than of spring in Germany.

Sea ice physicist Dr. Marcel Nicolaus from the Helmholtz Center for Polar and Marine Research told BILD: “It is actually the case that sea ice melts much more slowly than is often assumed. Due to the bright surface, only a fraction of the solar radiation is used for warming, while the larger part is reflected into the atmosphere.” This process is also called the albedo effect.

This effect prevents ice from melting

Graduate meteorologist Dominik Jung told BILD: “Ice is very bright and reflects a large part of the sun’s rays. This means that less heat is absorbed than, for example, on dark earth or asphalt. So the sun helps with melting less than you think.”

In addition, the ice must not only be heated to the melting point, but also actually melt, which requires a lot of energy. Dr. Nicolaus: “At the same time, energy is needed to heat the water in which the sea ice floats.”

Climatologist Dr. Karsten Brandt to BILD: “The Icebergs on the Baltic Sea are monuments of winter. There is still not enough energy to melt them.”

Numerous lakes are still frozen over

Weather expert Jung explains that the still cold and sometimes frosty nights slow down the thaw: “Then the surface freezes slightly again and the ice hardly loses any mass. This means that the melting takes longer.” Many freshwater lakes are also still completely frozen over. These include the Müritz in Mecklenburg-Western Pomerania, the Schermützelsee in Brandenburg and the Liepnitzsee north of Berlin. The low oxygen content in water can lead to: Fish die under the ice.

When the Baltic Sea will become ice-free

Brandt estimates that it will still take time until the ice disappears: “It could easily take another two to three weeks, especially because we will have our first real frost night again on Sunday.”

Especially at the Ostsee It takes time until the meter-thick icebergs that have been pushed together have finally melted away. On the partly still frozen ones Seen it can go faster. But the same applies there: “The water beneath the ice is usually just above freezing point. So there is hardly any heat coming from below that could help with melting,” Jung told BILD.