Waterspout observed over Lake Constance near Friedrichshafen

As Nerding further explained, the waterspout was visible over the lake for about 15 minutes: "Die Wasserhose war etwa 15 Minuten lang vor Friedrichshafen zu sehen." Other media reports, including the Vorarlberg news portal "vol.at", spoke instead of a duration of nearly 20 minutes. "Der Tornado war laut ersten Informationen rund 20 Minuten lang sichtbar", it stated there. According to the DWD, the column of air persisted for a total of around twenty minutes.

Wind speeds up to 150 km/h

Regarding the wind speeds, the meteorologist explained: "Die Windgeschwindigkeiten in dem Tornado seien schwer zu schätzen, aber er gehe von 100 bis 150 Kilometern pro Stunde aus." Accordingly, the vortex reached "Windgeschwindigkeiten von bis zu 150 km/h". Given this strength, it was a considerable, though locally limited, event. "Es handle sich dabei um ein 'beeindruckendes Schauspiel, dass am Bodensee fast jährlich vorkommt'", dpa quoted Nerding.

Meteorological background

Regarding the meteorological background, the DWD expert explained: "In der Atmosphäre haben wir in den untersten Niveaus Rotation, und diese Rotation hat jetzt im Zusammenhang mit der Gewitterzelle, wo es dann eben auch Aufwinde gibt, dafür gesorgt, dass wir die Bildung von einem Tornado hatten." As the Wetterring Vorarlberg added, the inflowing cold air over the warm Lake Constance was the trigger: "Durch die einfließende Kaltluft haben sich über dem warmen Bodensee mit der Konvergenz des Windes nicht nur heftige Gewitter sondern auch eine markante Wasserhose gebildet."

Regarding the general formation, a meteorologist explained: "Eine Windhose entsteht, wenn warme Luft über dem Wasser auf kühlere Luft trifft." This combination of temperature contrasts and wind shear is considered a typical prerequisite for such phenomena over bodies of water.

Path toward Lindau

After forming, the waterspout moved visibly away from the Friedrichshafen shore and, according to Kai-Uwe Nerding, was "kilometerweit zu beobachten". It then continued to drift in the direction of Lindau: "und zog dann nach Lindau weiter". Over the Bavarian shore, the vortex finally dissipated. "Laut Berichten des Vorarlberger Newsportals 'vol.at' blieb das Naturereignis nahezu 20 Minuten lang bestehen, bevor es sich wieder auflöste."

The platform Wetterring Vorarlberg (uwz.at) classified the event on Twitter: "Tornados oder Wasserhosen sind bei uns zwar selten, kommen aber immer wieder vor." The DWD also spoke of a rare natural spectacle: "Über dem Bodensee war am Mittwochmittag ein seltenes Naturschauspiel zu beobachten." The region has repeatedly been the scene of comparable but rare weather phenomena in recent years.

No damage, no injuries

No damage or injuries were reported according to initial information. "Informationen über Verletzte oder Schäden gibt es vorerst keine", the report stated. The water police also "meldete keine Notfälle". An eyewitness told the Swiss portal "20min" that he had briefly feared the vortex might reach the shore and cause damage.

Safety rules during severe weather

As the DWD emphasized, the rules of conduct during such phenomena are similar to those for other severe weather events: "Die Verhaltensregeln bei solchen Phänomenen gleichen jenen bei anderen Unwettern." The responsible parties recommended staying in sturdy indoor spaces: "In Innenräumen eines stabilen Gebäudes ist man am sichersten." In addition: "An Fenster sollte man sich nicht begeben."

Those who are outdoors at the time of such an event and where the wind strength is not too high can, according to the DWD, fall back on other protective options: "Wenn man draußen unterwegs ist und die Windstärke nicht zu hoch ist, kann auch ein Auto als Schutz dienen." These guidelines apply generally to severe thunderstorm situations, which occur repeatedly in the region.

Technical classification

The observed phenomenon is meteorologically classified as a waterspout or tornado over water. Over land, such a vortex is by definition a tornado; over water, it is often referred to as a waterspout. Both terms were used in the reports. "Wasserhose zieht über den Bodensee", was the brief summary; one observer spoke of "Gigantischer Tornado über dem Bodensee gesichtet".

The event was widely documented on social media. On the microblogging service Twitter, the Wetterring Vorarlberg posted a link to a video of the phenomenon. Numerous eyewitnesses posted photos and videos showing the rotating column of air over the water. International weather services and meteorologists also picked up on the event.

Further developments possible

The meteorologists pointed out that similar weather conditions could also occur on Lake Constance in the coming days. Since the combination of warm lake surface and inflowing cold air may persist, further waterspouts or strong thunderstorms cannot be ruled out. The DWD also referred to the general weather situation, which is causing unsettled weather in several regions of Germany and the Alpine area.

According to the DWD, the development on Lake Constance is to be monitored closely. "Solche Wetterphänomene sind am Bodensee eher selten", the meteorologist explained. The warning of severe thunderstorms in the Lake Constance area was maintained for the coming hours. Residents and tourists were asked to follow the guidance of the weather services.

The waterspout near Friedrichshafen is part of a growing number of documented events over European inland waters. Weather researchers have observed an accumulation of such phenomena for some years, including in the Alpine region. The exact classification of the strength is to be carried out by the German Weather Service in the coming days.

For the immediate Lake Constance region – including Friedrichshafen, Lindau, Wasserburg, and the Allgäu – there were no major restrictions on Wednesday afternoon according to the responsible authorities. Ship traffic on Lake Constance continued without major interruptions according to initial reports.