Hiking the GR5 in Luxembourg - Ouren to Vianden (Day 2)

After a pleasant and not so cold night under the tarp, we continue towards Vianden. The weather is a dream again, so that the first butterflies are already causing spring fever in some people.

The mountains were quite warm this morning, at around seven degrees, but the valleys were freezing cold and covered in hoarfrost. Side clouds rise from the meadows through the already warm February sun.

The hair rice

And there, in a valley, we discover a peculiarity called hair ice, or ice wool (see pictures above). From a distance it appears to be a fungus, but no, it is actually a quite rare form of ice, which can only be seen under very specific conditions. Here is a short summary from the LWG Bavaria: In this natural phenomenon, hairs of ice form on dead branches of deciduous wood. The special feature of this ice form is that it does not grow like an icicle at the ends, but from its base. For hair ice to form, it must have rained a lot for one or two days beforehand and the temperature must then be just around freezing point. This must be followed by a period of no wind. The temperature must then fall below freezing point so that ice can form. But it must not get too cold either, so that the process in the branch does not come to a standstill. The growth of the structures occurs because the water first freezes at the top and expands. But additional water pushes in from inside the branch. When it reaches the surface, it also freezes and expands. According to one study, hair ice is triggered by the mycelium of winter-active fungi, whose aerobic metabolism produces gases that displace the water present in the wood to the surface. It has been found that hair rice only grows on dead branches of deciduous trees colonised by the rose-tinted jelly crust (Exidiopsis effusa). The exact chemical and physical processes that give rise to the ice hairs remain obscure. However, the researchers discovered remnants of organic substances in the melted ice hairs. Among them was lignin. The hair-ice researcher Mätzler suspects that the lignin or a similar substance makes the ice retain its unusual shape. The hair rice might thus serve as a kind of antifreeze for the tree fungus. Thus, the water does not freeze in the branch where the fungus lives, but outside. The energy released during the freezing process also makes the branch slightly warmer than its surroundings. So much for today on the subject of biology.

Energy through water

Today, our hike goes less often along the Our River, but more often into the side valleys and over sometimes strenuous uphill passages, which make our strength dwindle more and more. After yesterday's exhausting day, we have a lot to fight for. In addition, there are impassable passages due to wind breakage on steep slopes, but we continue to fight our way up the mountain. At the top we reach the Vianden pumped storage plant, to our knowledge the only one in our immediate vicinity. The artificial water basin at 509 metres above sea level is used in conjunction with the reservoir in the valley to store energy in the form of water. In times when little energy is consumed in the form of electricity, the surplus energy is used to pump the water into the upper basin. When a lot of electricity/energy is consumed, the pumped storage plant produces energy by releasing water from the upper basin through the turbines, thus generating energy. So it's nothing more than a big battery on top of the mountain. The pumped-storage plant was built from 1954 to 1964 and dates back to plans dating from 1925. So much for today on the subject of technology.

From here, it's a leisurely downhill towards Vianden, past the cable car that likes to take tourists up the mountain, and then onwards with beautiful views of Vianden Castle. Our tour ends today and here earlier than planned, as our batteries were at their minimum. At this point we would like to praise Luxembourg's public transport system. In Vianden, which is quite rural, buses run every hour on Sundays to nearby Diekirch - free of charge, just like in the rest of Luxembourg. That would be unimaginable in Germany. So we took advantage of this opportunity and were driven to the car parked at our actual destination. See you soon on the GR5, the first stages were more than scenic!

What is the GR5?

The GR5, a European long-distance hiking trail! The GR5 starts in the Netherlands at Hoek van Holland, crosses Belgium, Luxembourg, France via the Vosges, the Jura, the Maritime Alps and ends after 2080 kilometres at the Mediterranean Sea near Nice. And what does that have to do with us? People like to set goals in their lives - and why not be able to say at some point that you have walked from the North Sea to the Mediterranean in hiking boots? So now we have a new project! As time will allow, we will take on the GR5 and hike it in sections. Sometimes only as weekend tours over stretches that are close to us, or as longer tours when holidays and Corona rules allow. Let's go, bonjour GR5! Or Moieeen, as the Luxembourgers like to greet each other at any time of the day or night!

Video of the hike on the GR5

The tour on the GR5 at Komoot