Alps Climate

The Alps are a classic example of what happens when a temperate area at lower altitude gives way to higher-elevation terrain. Elevations around the world that have cold climates similar to those of the polar regions have been called Alpine. A rise from sea level

into the upper regions of the atmosphere causes the temperature to decrease (see adiabatic lapse rate). The effect of mountain chains on prevailing winds is to carry warm air belonging to the lower region into an upper zone, where it expands in volume at the cost of

a proportionate loss of temperature, often accompanied by precipitation in the form of snow or rain.[62] The height of the Alps is sufficient to divide the weather patterns in Europe into a wet north and a dry south because moisture is sucked from the air as it flows over the high peaks.[63]

The Aletsch Glacier with pine trees growing on the hillside (2007; the surface is 180 m (590 ft) lower than 150 years ago)
The severe weather in the Alps has been studied since the 18th century; particularly the weather patterns such as the seasonal foehn wind. Numerous weather stations were placed in the mountains early in the early 20th century, providing continuous data for climatologists

.[12] Some of the valleys are quite arid such as the Aosta valley in Italy, the Maurienne in France, the Valais in Switzerland, and northern Tyrol.[12]