The Alps are the highest and largest mountain range in Europe. The highest peak is the Montblanc with a height of 4807 m. The young fold mountains are divided into the Northern Limestone Alps, the most prominent Central Alps and the heavily karstified Southern Limestone Alps. The highest areas are covered by glaciers, relics of the ice ages that have significantly shaped the surface of the Alps. Climate and vegetation are largely determined by the relief.
Important economic factors are the declining alpine farming and the expanding tourism. The constantly increasing transit traffic, especially in freight transport, is becoming a major problem. To protect the Alps and their residents, the neighboring states signed the Alpine Convention.
The Alps extend in a 1200 km long and 150 to 250 km wide arc from the Gulf of Genoa to the Hungarian lowlands and cover a total area of 220,000 km² (Fig. 1). The Alps reach in the south to the Apennines. The pass of Altare near Genoa is the border here. From there they move in a wide arc to the west and north to Lake Geneva and from there east to the Danube near Vienna. In the northeast the Alps merge into the Carpathians, in the southeast into the Dinaric Mountains. In the east they border on the Hungarian lowlands and in the south on the Po Valley. The foothills of the Alps are in front of the north. It extends in the north to the Danube, in the west with the Swiss plateau to Lake Geneva and the Jura. The highest peak in the Alps and also in Europe is the 4807 m highMontblanc, which is on the border between France and Italy. Seven countries have a share in the Alps: Germany, France, Italy, Liechtenstein, Austria, Switzerland and Slovenia.
Long mountain chains and valleys structure the high mountain landscape. The Eastern Alps are lower than the Western Alps. The valleys widen to the east, and large basin landscapes reach far into the interior of the Alps. In the western Alps, the mountain ranges are more closely bundled.
The Central Alps form the watershed between the North Sea and the Mediterranean Sea, the Eastern Alps between the Black Sea and the Mediterranean Sea. As a climatic divide, the Alps separate the climatically rougher Central Europe from the Mediterranean south, because the Alpine ridge largely prevents the transport of cold air masses from the north to the south or warm air masses from the south to the north.
Structure and surface design
The Alps are part of a geologically young system of folded mountains that stretches from the Atlantic Ocean to the Black Sea. Around 175 million years ago there was a large ocean at the site of today’s Alps and the Mediterranean, the bottom of which consisted of granite, gneiss and slate (Fig. 2). Lime and clay layers were deposited on this seabed. Over the course of millions of years, deposits of rock formed several thousand meters thick. The Alps essentially had their fold structure in the Cretaceous Period around 100 million years ago and in the subsequent Tertiary during the phase of the Alpine mountain formation receive. About 40 million years ago there was a period of particularly strong tectonic processes in the subsurface, which was accompanied by volcanic activity. The mountains are characterized by folds and overthrusts. According to the theory of plate tectonics, the layers of the earth stacked up in the collision zone between the African plate and the European plate due to plate movements towards the Alps.
The structure of the Alps (Fig. 3) results in the Central Alps, Northern Limestone Alps and Southern Limestone Alps.
With the elevation of the Alps, the erosion of the bedrock began at the same time as the weather. In the middle part, today’s Central Alps, uplift and erosion were greatest. There, the overlying limestone and clay layers have been completely removed, and the older basement mountains now form the peaks. The northern and southern Alps, on the other hand, which were not raised that high, are made up of limestone. One speaks therefore of the Northern Limestone Alps and the Southern Limestone Alps, which are more karstified.
Today’s surface shapes are largely a result of the Ice Age. The Alps are the mountains with the most shapes in Europe. They owe this to the diversity of their rocks and the reshaping effect of the ice ages, in which the valleys and passes were widened by powerful glacier flows (Fig. 6). On the northern and southern edge of the Alps, deep valley lakes such as Lake Constance, Lake Geneva and the northern Italian lakes formed. In the foothills of the Alps, mighty moraines were heaped up, some of which enclose lake basins such as the Chiemsee or Lake Garda.
Another characteristic of the Alps is the stepped construction of the high valleys with their alternation of narrow gorges and wide basins as well as the waterfalls at the confluence of the side valleys into the main valley. Steep-walled slope niches, the cirque, often appear, which often have small lakes in the summit area.
Ice and snow
The once mighty glaciers have receded. Today only the inner and highest parts of the Alps are glaciated. The ice permanently covers 1.5% of the entire Alpine area. The extent of the glaciers is subject to fluctuations in which the tongues of ice either advance or melt. Maximum expansions were recorded around the year 1600 and around 1850. Since then, glaciers have generally been receding sharply. This is very likely also due to global warming. The largest alpine glacier is the Great Aletsch Glacier in Switzerland.
Avalanches often occur in the Alps in the winter months. Suddenly large amounts of snow and ice slide off steep mountain slopes. This happens when the thickness of the snowpack on sloping ground becomes too thick and it loses its inner cohesion, when the snow is soaked with water or due to human influences, for example skiing or snowboarding. The heavy deforestation of the forest, which represents the best avalanche protection, promotes avalanche formation, especially in the new ski areas. One tries to reduce the danger by erecting artificial obstacles in the known avalanche paths.
After heavy rainfall or at the time of the snowmelt, rockslides and mudslides can slide down into the valley on steep slopes or in stream beds in the Alps. Mudflows, mixtures of water, soil and rocks can have just as devastating effects as avalanches.