Heatwave: What Is the “Hairdryer Effect” on Vegetation?

Paris – 24.06.2026: In recent days, an extreme heatwave has struck France, with temperatures exceeding 40°C in several regions. These conditions have triggered a worrisome effect on vegetation known as the “Hairdryer Effect.” This term describes a sudden and intense drying out of plants caused by the combination of extreme heat, strong winds, and low humidity.

Under these conditions, water evaporates from plants faster than the roots can absorb it, leading to rapid drying. This process can damage vegetation within a few hours and make it susceptible to fires. Agroclimatologist Serge Zarka explains that plants try to conserve water by closing their stomata, but this impairs their ability to regulate temperature. When the internal temperature of the plant exceeds 40°C, its metabolism can collapse, resulting in the death of the plant.

This effect was particularly observed in the Centre-Val de Loire region, where temperatures over 42°C were recorded on June 22, 2026. The combination of scorching heat, strong winds, and humidity below 20% led to dramatic drying of soils and plants. Early signs of crop losses and damage to fruit trees have already been noted in this region.

The impacts of the “Hairdryer Effect” are not limited to agricultural crops. Forests and natural vegetation also suffer under these conditions. In the forests of the French Massif Central, trees have been observed shutting down vital functions to conserve water due to repeated heatwaves, leading to their slow death.

French authorities have responded to these extreme weather conditions by placing 26 departments under Orange Alert for heatwaves. Additionally, water restrictions have been implemented in 39 departments to reduce water consumption and minimize fire risks.

Experts warn that such extreme weather events may become more frequent in the future due to climate change. A 2025 report by Météo-France predicts that the number of heatwaves and tropical nights in France will increase, potentially causing significant impacts on the environment and agriculture.

Given these challenges, professionals emphasize the need to develop adaptation strategies to strengthen the resilience of agriculture and natural ecosystems to extreme weather conditions. These include selecting heat-resistant plant species, improving irrigation systems, and promoting sustainable agricultural practices.

Overall, the “Hairdryer Effect” highlights the vulnerability of French vegetation to extreme weather conditions and underscores the urgency of taking measures to protect the environment and agriculture.