High Alps
The High Alps are those parts of the Alps unsuitable for habitation or seasonal transhumance. This includes all regions higher than 3,000 m above sea level, as well as most regions between 2,500 m and 3,000 m.
The High Alps have tundra or ice cap climate rather than the Alpine climate eponymous of the Alpine region at 1,800-2,500 m, above the tree-line but still amenable to transhumance economy.
Exploration of the High Alps began in the 18th century, with Horace-Bénédict de Saussure. The first ascent of the highest peak of the alps, Mont Blanc, dates to 1786.
All important mountain passes in Switzerland are below 2,500 m but there are a few minor foot passes above 3,000 m: Schöllijoch at 3,343 m, Theodul Pass at 3,301 m, Zwischbergen Pass at 3,268 m, and others. Of historical interest is the Schnidejoch at 2,756 m which appears to have served as a pass since prehistoric times. In other Alpine countries there are higher road passes, such as the Col de l'Iseran in France and the Stelvio Pass in Italy.
The alpine line of perpetual snow is not fixed. The occurrence of favorable meteorological conditions during several successive seasons can increase the extent of the snowfields and lower the limit of seemingly permanent snow, while the opposite may cause the limit to rise higher on the flanks of the mountains. In some parts of the Alps the limit is about 2,400 m elevation, while in others it cannot be placed much below 2,900 m. As very little snow remains on rocks angled more than 60°, this is soon removed by the wind, some steep masses of rock remain bare even near the summits of the highest peaks, but as almost every spot offering the least hold for vegetation is covered with snow, few flowering plants are seen above 3,350 m.
The climate of the glacial region has often been compared to that of the polar regions, but they are very different. Here, intense solar radiation by day, which raises the surface when dry to a temperature approaching 27°C, alternates with severe frost by night. There, the Sun, which never sets is only able to send feeble rays that maintain a low temperature, rarely rising more than a few degrees above the freezing point. Hence the upper region of the Alps sustains a far more varied and brilliant vegetation.
| relief map of the Alps with altitudes above 2,500 m highlighted |
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