Читать книгу The Swiss Alps онлайн

19 страница из 176

Projecting into Italy Canton Ticino, whose mountains belong to the Lepontine and Adula Alps, enjoys the most settled weather, with a Mediterranean climate giving consistently hot and sunny days in summer and comparatively mild winters. Lying in the rain shadow of the Bernese Alps, the Pennine Alps of neighbouring Valais are among the driest.

Although occurring with some frequency in summer, storms in the Bernina and Bregaglia Alps are generally less dangerous than those experienced in the Bernese Alps where they often arrive with little warning and sometimes last for many hours, or even days. At high altitudes bad weather is not only physically uncomfortable for climbers caught mid-route, but rocks can rapidly cover with snow, ice or verglas to turn an otherwise straightforward climb into a real epic. Mist and cloud can also make glacier crossing a hazardous exercise.

The Swiss Alps are affected by unusual seasonal winds; the bise comes from the north and can be bitterly cold, even in summer, with night frosts and generally settled weather providing good climbing conditions. The föhn is a very different wind. This blows from the south or southwest with hot air being sucked from the Mediterranean or even the Sahara. As the air is forced to rise over the Alps, it cools and rain or snow falls on the south side of the mountains, with floods sometimes resulting. Having shed its moisture the föhn is then funnelled through the northern valleys, drying and warming as it does. Snow cover diminishes, and conditions for climbing are bad.