Tornado precursor

Funnel cloud observed in the Krems area

Funnel clouds (symbolic image) are the precursors of a tornado.

(Bild: AFP)

The precursor of a tornado - a so-called funnel cloud - was observed in the Krems area in Lower Austria on Thursday afternoon. Photos of the weather phenomenon were posted on social media. There have been no reports of any damage so far.

The funnel cloud is the preliminary stage of a tornado, said Georg Pistotnik from Geosphere (formerly ZAMG) Austria. Tornadoes are formed "when a thundercloud sucks up a vortex of air", explained Pistotnik. On average, this weather phenomenon has occurred four times a year in Austria since 1998.

Approaching cold air as a trigger
It was not yet clear whether the cloud, which was spotted north of Krems at around 1.40 p.m., had made contact with the ground. According to ORF meteorologist Manuel Oberhuber - who published pictures of the weather phenomenon on X (see post below) - "converging winds in the vicinity of several showers and the approaching cold air from the west" were the trigger for the funnel cloud.

Funnel clouds can turn into tornadoes
In contrast to a tornado, a funnel cloud does not refer to the entire vortex, but only its visible part. The vortex itself continues downwards below the funnel cloud and can therefore merge into a tornado at any time.

It is important to note that the continuous rotation does not have to be visually recognizable by a "cloud tube" in order to exist. Meteorologists speak of a tornado, which is also known as a large tornado, as soon as turbulence or damage appears on the ground beneath a funnel cloud.