Nature is ready, let that snow fall down. It is autumn, the leaves change color waiting for the autumn storm that will blow them from the branches. The Alps yearn for water after a dry summer/autumn and the glaciers beg for snow. But no matter how much nature calls for water and snow, the weather chooses its own course, with a helping hand by us. Record after record has been broken. 2018 is on track to become the warmest year ever since the start of measurement in Austria. No less than 127 summer days of 25 degrees or more have been measured in recent months. And it's not over yet. They recorded a whopping 30 degrees in the Swiss region of Ticino yesterday. A temperature above 30 degrees was never measured before in Switzerland in the month October.
The high temperatures in the Alps are caused by a current from the south that transports warm air from northern Africa to Europe. At the same time, polar air from the North Pole is on its way to the west of Europe. These two air masses collide with each other this weekend. The Alps cool off a little, there is a lot of precipitation in the valleys and the low mountain ranges and a lot of snow in the high alpine. It will rain, as in: intense. It will snow heavily in the high alpine where large quantities can come down locally. In this forecast:
That nature is ready for it is clearly shown by the images below from the main alpine ridge in Austria. Where no snow can be seen, you can recognize the autumn immediately. The snow line, the blue sky and the autumn colors. It's wonderful to see the first snow on the highest peaks of Austria.
But the weather won't be as good this weekend as it was yesterday.
The Alps are stituated on the separation of warm and cold air this weekend. The cold air hits the north and west of the Alps on Saturday. According to the latest calculations, the cold air will position itself near the highest peaks, which is just a little bit more to the north than previously calculated. But at such a stationary front it is very difficult to predict where the snow line will be located exactly and it can also vary from valley to valley. Assume for the time being that the snow line in the west and north of the Alps temporarily will be between 1500 and 2000 meters (and sometimes even lower), while on the south side of the Alps it will be around 2000 to 2400 meters this weekend. This results in a lot of snow visible on the snow maps. It definitely looks like winter when you just look at the snow maps.
The snow maps show the cumulated snowfall for a certain period (the amount of snow that comes down). But that amount of snow always gets a little less in reality. In the middle of winter, this is because snow settles because its own mass and under the influence of the weather.
TIP: check out this article about 'How much fresh snow?! The discussion about centimeters.'.
This is often even more complex in the autumn. Because without a cold base freshly fallen snow is attacked from two sides. Not only does the snow cover melt through incoming heat and rain, but the surface is often still warm. If there is rain after snowfall, the snow will quickly disappear from the map. The snow map is correct, because there is indeed snow coming down, but this melts quickly through rain and a warm surface. If you look at the snow maps, definitely look at the development of the temperature as well (especially in autumn).
Check out the temperature charts for Saturday (left) and Sunday (right) below. Blue is below zero, yellow and orange above zero. It is good to see how much warmer it is on Sunday. The valleys show much more orange and yellow colors. In addition, it is also significantly warmer in Austria.
TIP: check our forecast page for detailled temperature maps
There is snow coming down in the lower parts of Austria on Saturday (which can be seen on the map below on the left), but if the high temperatures come in on Sunday (map on the right below), it will rain in large parts of the Dolomites and Carinthia. At the same time, a Föhn will come in in the east of Austria. Say goodbye to the snow that came down on Saturday.
TIP: check our forecast page for detailled snow maps
There's more than meets the eye when you look at the snow maps. If you only look at the snow maps, you may come to the wrong conclusion. The winter is definitely not coming in this weekend. It will be a very wet hick-up. There's a reason why I'm talking about a base for the high alpine and lots of rain in the valleys for days. The soil is very dry and it will have trouble absorbing the water. That is definitely going to cause troubles, especially on the south side of the main alpine ridge where huge amounts of water will come down.
During the next three days (Saturday, Sunday and Monday) the base for the high alpine will be formed. Let's have a look at the snow map again.
Forget about all the snow in the valleys. Also forget about all snow below 2000-2400 meters. You can expect a significant amount of snow above that altitude. It is only the first real dump this fall and let's hope there will be a lot of snow coming down. We really need that in the Alps, but it's definitely too early to wax your skis or board.