Friday, February 1, 2019

Cross Alpine Weather Contrasts

Although the northern Alps have been favored for snowfall for much of the cool-season so far, the southern Alps are getting some action today.  Below is the GFS forecast for 800-mb (roughly 2000 meters or 6500 feet above sea level) winds and relative humidity valid 0900 UTC Friday (2 AM MST).  Note the south flow impinging on the south side of the Alps, the strong height gradient across the Alps, the the lower relative humidity air to the north.
There is a great web site,, for examining web cam images from the eastern Alps.  On the site, one can access not only real-time images, but also historical images, and be able access web cam images via a map that shows the direction and area surveyed.  This is hugely helpful for weather applications.

The contrast across the Alps today is very consistent with the southerly flow.  Looking north from Kronplatz in northern Italy on the south side of the Alpine crest, skies are obscured and it may be snowing (hard to tell for sure).  This is actually the clearest image in the past couple of hours based on a time lapse.

Looking south from Seegrube above Innsbruck one can see the orographic clouds and some snow that is spilling over the Alpine crest.

However, Innsbruck is still in the Alps, with mountains to the north.  We can go further north, to Unterammergau in Germany and near the northern Alpine foothills and here there are only high clouds.

In the western U.S., where most mountain ranges are oriented north-south, most (but not all) storms tend to favor the western side and mountain crest.  In contrast, the eastern Alps run predominantly east-west and are quite wide so that the windward side can vary from day to day or even during the day.  Mean annual precipitation in the eastern Alps, including western Switzerland, Austria, southern Germany, and northeast Italy, shows distinct bands of heavier precipitation along the northern and southern Alpine "rims".  Note also that the interior Alps in this region is drier, despite higher mean terrain elevations. 

Source: Christoph Frei, ETH
For long-term ski vacation planning, you can't really bet on a winner in the south side or north side competition.  You get what Mother Nature gives you.  Today, if you want fewer clouds and a bit of sun, the north Alps are the place.  If you want snow, the south Alps or near the Alpine crest. 


  1. I'd like a high res version of that precipitation map.

    One note that you may already know. The Alps get more precipitation summer than winter, unlike western North America. Therefore it's not certain that the map is a good surrogate for Alps snowfall. The known high snowfall areas around Warth and Lech/Zurs in the northwest corner of Austria is blue on that map. But the high snowfall areas in France donlt stand out much at all. It is known that the SE corner of Switzerland and the adjoining parts of Austria and Italy are relatively dry because most storms have to get past other mountains to reach those areas.

    We have been going to the Alps in mid-January for 2+ weeks each of the past 3 seasons. We figured out that you cant bet on a winner in advance, so we just get out plane tickets and a car rental, then start choosing resorts about a week before we leave.

    2016: Lech/Zurs (booked in advance because of high demand), Kitzbuhel, SkiWelt, Saalbach, 3 days in Venice, Ischgl, gateway Zurich
    2017: Aosta, Dolomites (stayed in Arabba), Monterosa (stayed in Grosseny), Cervinia, Chamonix, 2 days in Annecty, La Clusaz, gateway Geneva.
    2018: Arosa, St. Moritiz, Engelberg, Andermatt, Morzine (Ported du Soleil), gteway Geneva.

    As you can see, the last two years we did most of the skiing far from our gateway airport. But the Alps are compact by North American standards. At the same latitudes, the entire Alps from Geneva to Slovenia would fit between Lookout Pass and Red Lodge in Montana. So relocation drives were 4-5 hours at most, and usually less.

    1. Tony:

      Some high resolution precip analyses and perhaps a seasonal breakdown are available at Play around with the options under precipitation.

      ZAMG, the Austrian Weather Service, has precip analyses for the Alpine region as well, but they are only 5 minute (about 5-km) grid spacing. I think the dataset does include monthly analyses. You are correct to note that the seasonality matters, although the general pattern doesn't change too much. Nevertheless, it would be good to put together something for the months that matter.

      BTW, you were smart to book in advance for Lech/Zurs. Lodging from now through march is booked up pretty solidly here.


  2. Lech/Zurs is the best logistics base for skiing the Arlberg, but lodging is much more limited than in St. Anton and much of it more expensive. Thus I've made the exception and booked early there in both 2013 and 2017. The stellar snow record of Lech/Zurs (~400 inches Nov-Apr at ski elevation) provides some margin of error vs. advance booking most other places.

    The next 3-4 weeks are the midwinter school holiday crunch. Even though it's an optimal time for snow conditions, it's bad for lodging cost/availability so not recommended for resort skiing if you can find another time frame.

    Mid-to-late March after those holidays is also a good time, but you need to pay a lot more attention to altitude/exposure then.