How the US “bomb cyclone” is linked to Switzerland’s thaw The Brexit trade deal was supposed to help UK businesses – but for many it’s useless

In terms of weather, we are currently experiencing special days. The US is preparing for heavy snowstorms and temperatures well below freezing, while in Basel the thermometer rises to 13 degrees by Christmas. Despite the high temperatures, the second highest avalanche warning level has been declared for Lower Valais, while there is a risk of flooding in the valley.

But how do such special weather conditions come about? The meteorologist informs us: Much depends on the jet stream that meanders over the globe. On one side of the jet stream there are temperatures below zero, on the other side thaw.

Danger of avalanches and floods

“The jet stream flows in waves around the world. The US is currently in the grip of an advance of cold air from the north, in Europe we feel the warm air from the southwest,” says meteorologist Gabriela Granat of Meteo Schweiz. That is why the Christmas thaw also falls in Switzerland this year.

Although temperatures are in the double digits in the lowlands, the Institute for Snow and Avalanche Research SLF meanwhile declares the second highest danger level in some regions. The reason for this is the massive precipitation that accompanies the thaw.

The snow line is well above 2000 meters, but: “There will be a lot of snow, especially above 2500 meters. In addition, strong winds cause drifts, which then increase the risk of avalanches, “says Granat. This particularly affects the Lower Valais, where the risk of avalanches in the mountains and the risk of flooding in the valley around the Arve is high.

Deadly storms in the United States

A view of the US shows what it looks like on the other side of the jet stream. Here, meteorologists warn of huge snowstorms and temperature drops – and now even a “bomb cyclone”. Means: Within 24 hours the air pressure drops drastically and with that there is an enormous drop in temperature.

There is also a chance of extreme wind and heavy precipitation. All this complicates travel conditions in the US, where many people travel by car or plane to visit relatives in other parts of the country. In addition, the cold and the wind are life-threatening, especially for the nearly 600,000 homeless people.

Climate change affects the jet stream

So right now we are witnessing what happens when the jet stream forms bigger bulges. In one place the temperatures drop drastically, in the other they go the other way. The stronger the jet stream, the stronger the boundary with the icy polar air.

Climate change and the associated rise in temperatures in the Arctic are weakening this natural boundary. That is why weather conditions such as we are experiencing now are becoming more and more common: the jet stream can no longer tame the polar air. (lion)