Aufbauende Umwandlung

The marmot greets us daily with sunshine and a mostly cloudless sky. Especially near the surface, there is a massive temperature gradient of just a few centimetres in the snow cover - often despite plus temperatures up to high altitudes.

After a brilliant start to the season in September and October, November brings us back down to earth with the autumnal high pressure - as reported by the WeatherBlog. On the sunny side, the snow cover bubbled out again right up to the top, while on the shady side, faceted weak layers formed in this constellation of settled but thin old snow cover and persistent fine weather.

Greetings, dear WeatherBlog readers! We are starting the season, despite high pressure and the corona crisis, because: Weather always works. And at some point, the weather will change again and so will the lockdown situation. And then you want to be well prepared! The other PowderGuide weather services (fresh snow forecast, PowderMap) will be switched on when it looks a bit more wintry.

Hazard pattern 4 - cold on warm, warm on cold - occurs when there is a large temperature difference (more than 5°C) during the snowing process or between the snow surface and the fresh snow. As the name suggests, it can occur in both temperature directions, regardless of whether it snows cold on a warm surface or vice versa.

A built-up, loose snow cover from the ground to the snow surface is a product of prolonged periods of fine weather in early and mid-winter. This snow, known as nap powder, forms a weak layer that must be taken seriously as soon as it has been snowed in. This is currently the case in wind-protected and little-traveled W-N-E slopes at high altitudes.

The PowderAlert has already announced it and anyone looking out of the window in the Northern Alps will notice it: it's been a long time since rain or even snow instead of sun and high fog! A nice change that we have a cold front from the northwest to thank for.

Everything back to the start. After a good start, hardly any snow has fallen since Christmas and it feels like we're back in November, but finally Ullr has seen sense and sends us a winter greeting again. Unfortunately, he has to get back into the groove and it won't last, but more on that in the alert.

You often see that the lower snow layers are missing from profiles, but aren't these also important? Basically yes, but since you can't assess an entire slope with a profile, but "only" (and yet very much) locate the snow layers, snow forms, weak layers, etc., as well as observe fracture initiation and fracture propagation, you don't necessarily have to dig a three-metre-deep hole.

Powder was still to be found on shady slopes and flatter sunny slopes this week, while broken snow was already prevalent on steeper sunny slopes. Sleet deposits could also be observed again and again.

The snow surface has taken a turn for the worse again in terms of skiing. After a Christmas season blessed with powder and good weather, the crowds, wind and sun have left their mark. That's why we'd better get back to a snow profile than skiing.

Snow crystals begin to change on their way from the cloud to the ground. Perhaps a layer of air is warmer and the crystal thaws slightly, or several crystals stick together to form large flakes. If it is windy, the fine branches of the crystals break off. Once they reach the ground, things don't calm down - that's when the changes really begin. For skiers, the decomposing and building transformation is crucial:

Despite the warmer temperatures in the fine weather phase, the snow surface on shady slopes remained mostly loose. On the other hand, slopes exposed to strong sunlight - especially at lower altitudes - became damp on the surface and a cover could form due to cooling.