Lake appears to be smoking at dawn

A lake in France appeared to be "smoking" at dawn, with white wisps rising gently from its surface, creating the illusion that the water was about to boil. This visual effect, however, was not due to actual boiling but to a natural atmospheric phenomenon.

Evaporation fog explained

The phenomenon is known as "evaporation fog," which occurs when cold air passes over still-warm water. This causes the water to evaporate and form tiny suspended droplets, creating a fog-like appearance. This effect is common when there is a significant temperature difference between the air and the water.

2026 summer was the hottest in France

The summer of 2026 was the hottest ever recorded in France, with an average temperature of 24°C. This was followed by a mild autumn that allowed lakes to retain significant heat, contributing to the conditions that led to the evaporation fog.

Temperature contrast creates conditions

The National Weather Service in the United States and Météo-France describe this phenomenon as occurring when cold air glides over warmer water, causing evaporation and the formation of tiny suspended droplets. This effect is particularly noticeable near lakes during the transition from summer to winter.

2026 summer linked to climate change

Virginie Schwarz, CEO of Météo-France, has described the summer of 2026 as almost impossible without climate change. The average temperature of 24°C over June, July, and August, combined with 53 days of heatwaves and 45% of the territory exceeding 40°C at least once, highlights the impact of global warming.

Cold air and warm water create fog

Forecasts indicated possible frosts below 0°C at dawn from the beginning of November, especially in the north and center of the country. This sudden shift from warm to cold air creates a thermal shock with the water, increasing the chances of seeing evaporation fog on lake mornings.

Driving restrictions during fog

If visibility drops below 50 meters near a body of water, the maximum allowed speed is 50 km/h, even on highways. This rule is in place to ensure safety during conditions when fog can significantly reduce visibility.