Causes of foehn winds in the Alps

The foehn effect occurs in the northeastern region of the Alps in summer. Because in summer the Mediterranean region is under the control of the subtropical high, while the northern European region is under low pressure. The wind blows from the south to the north and forms a northwest wind under the influence of the geostrophic deflection force. The wind is blocked by the Alps and forms a terrain on the south slope, that is, the windward slope. The water vapor content in the wind decreases sharply after the rain. The wind crosses the mountains and sinks in the north of the mountains. It is a dry and hot wind, that is, foehn wind