In brief
In the Gironde region near Bordeaux, thousands have been forced to flee as Pyrocumulonimbus or fire–generated thunderstorms, a new type of weather event, explode across the landscape. These towering clouds lift hot air, smoke and water vapour high into the atmosphere, letting wind currents carry embers miles beyond the fire front and even spark new fires with lightning. Historical parallels are already seen in Australia’s Black Summer 2020 and in California’s 2021 blaze season, where similar pyrocumulonimbus storms increased fire spread dramatically. Climate change is predicted to make such events more frequent, putting firefighters and communities in unprecedented danger.
Tens of thousands of residents have been evacuated from the Gironde region surrounding Bordeaux as a new form of fire‑generated weather—called a pyrocumulonimbus, or fire‑generated thunderstorm—erupts across the landscape.
These towering clouds form when extreme heat from a wildfire pushes hot, smoke‑laden air upward. The rising column cools, condenses into cloud droplets, and in strong, unstable conditions expands into a cumulonimbus type of cloud that can produce lightning, high winds and violent turbulence that flings embers far ahead of the fire front.
Scientists first reported the phenomenon while fighting blazes in France, noting it had never before been seen in the country. Similar events were recorded during Australia’s Black Summer 2019‑20, where embers travelled up to 18 kilometres ahead of the blaze, and during California’s 2021 wildfires, where smoke‑filled clouds rose a mile above the forest.
The growing frequency of these fire‑generated thunderstorms is linked to hotter, drier conditions brought on by climate change, and authorities warn that fires may burn for months under these volatile skies.
If you find yourself in an affected area, contact local emergency services and consider reaching out through available online channels for real‑time updates.
