Temperaturgradient

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.

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.

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.

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.

The great early winter conditions south of the Inn are continuing. There is now another 20 cm of fresh powder locally. Avalanche conditions, snow quantity and snow quality are in an optimal range for early December.

In the Southern and Central Alps there is often already a very thick snow cover. Weak layers that have been built up (old snow problem) can only be found on glaciers directly on the glacier ice. In other words, where the snow from early fall has remained. Otherwise, the snowpack structure is very good - and will most likely remain so in the snow-rich regions.

High Dorit and Erika have been bringing warm and practically precipitation-free weather for many days. On the sunny side, you can now find spring-like conditions with firn, depending on the altitude. On the shaded side, you can still catch a few turns of good powder - at least where the wind hasn't worked - despite a zero degree limit of over 3,000m at times. Why?

At first glance, snow profiles seem complicated. However, if you know a few basic terms, this impression is quickly put into perspective. But even if you can read profiles, it takes some practice to draw the relevant conclusions from them. The most important thing, however, is to be able to visualize the snow cover and its layering in the terrain. An example:

In the current season, it was noticeably more dangerous in sunny areas than in shady ones. This is due to a special form of weak layer formation known as the "cold on warm hazard pattern".

Far too little attention is paid to humidity in everyday snowmaking. However, its influence on the snow cover is just as important as the temperature. Let's consider a marriage in which complete equality between the two partners is the reality.