Wind conditions in Serre Ponçon in real time

Wind conditions for the last 24 hours in Serre Ponçon

At Serre Ponçon, the daytime thermal wind blows from the West/Southwest, conditions fluctuate between 15-25 knots - or 28 to 45 km/h - in May, June, July (because the lake water, resulting from snowmelt, is lower than 19°) and weakens between 8-12 knots - or 15 to 22 km/h - from the end of July to the beginning of September (when the lake water warms up).

The mountains surrounding the lake and the temperature variations between day and night, which occur from the fine weather, favor the appearance of almost daily thermal breezes from midday until late afternoon.

Stable and regular conditions, more pronounced from Savines-le-Lac (Venturi effect) going up towards Embrun, make this area THE ideal spot for sailing in Serre Ponçon.

But what is a thermal breeze?

A thermal breeze is a meteorological phenomenon that results from the temperature difference between the surface of the land and the lake. It does not exist when the water temperature and that of the land are the same.

The terrain plays an amplifying role in this phenomenon (accelerating the air currents flowing down the slope).

Under the action of solar radiation, the land heats up faster than the lake water.

By conduction, the air in contact with the land surface heats up and rises. This creates a thermal depression above the land. The warm air that has risen into the atmosphere is immediately replaced by colder, more humid air from the lake. This cold, humid air in turn heats up and rises. As it rises, it cools and condenses in the form of a cumulus cloud.

Throughout the day, the breeze strengthens.

Factors influencing thermal breezes:

- The nature of the ground, the relief, and the structure of the air mass play an important role in the establishment and intensity of breezes.

- Significant relief will influence the strength of breezes. Slope breezes will combine with thermal breezes.

The establishment of a thermal breeze depends on the characteristics of the surrounding air mass (pressure and temperature). A thermal breeze can only develop in a situation of vertical instability.

The air bubble rising from the ground is then warmer than the ambient air; it rises and then condenses in the form of Cumulus or Cumulonimbus clouds, which are characteristic of an unstable air mass. Its rise causes a "suction." The thermal breeze mechanism can then be triggered.

When the air mass is stable or in the case of a thermal inversion (the air in the lower layers is colder than the air in the upper layer), lift is impossible and the breeze cannot establish itself. The phenomenon of thermal inversion is commonly observed in valleys in winter and generates seas of cloud.