The dust demon that formed in Alsace was not a hurricane, but a 'dust demon'

The dust demon that formed in Alsace was not a hurricane, but a ‘dust demon’

A wonderful whirlwind of dust arose on the 30th of July in Alsace-Poso. Despite appearances, it is not a hurricane, but a “dust devil”, a “dust devil”, a relatively harmless natural phenomenon. We explain to you.

This very remarkable phenomenon occurred on Saturday 30 July in the middle of the afternoon, in the Ormangen sector, in Alsace-Posseau (Bas-Rhin): a whirlwind of sand dust, one to twenty meters in diameter and a few dozen – even at a height of a few hundred meters . In about a minute, it moved several hundred meters, before ending up in a field.

Watch the event, the young student Matisse Grosnickel, who was driving his car. “At first, I didn’t see what it was” He says. “I thought that a farm machine was passing by and shooting a cloud of dust. But I saw that this cloud was moving fast, that it was circular in shape, and there was no farming machine behind it.”

Intrigued, Matisse Grosnickel parked his car and took his phone for a shoot. In 25 seconds, he succeeded in capturing the whirlwind in its astonishing development, until it lost its intensity and dislocated it.

Strange aesthetics: “It was beautiful and impressive to see” sums up. But also a little annoying: “At first glance, it looks a bit shocking, a picture of what’s going on right now.”

“Drought is strongly felt in Alsace. The land is so dry that hurricanes are forming. A very cool experience. Global warming is here” He then wrote on his Twitter account to accompany his video.

For Alsatian meteorologists, who read his video, this analysis is only partially correct. Because this whirlwind has nothing to do with the hurricane. It is simply the “dust devil”, the “dust devil”, a well-known and widespread natural manifestation.

‘A fairly harmless phenomenon’ Florian Knoll, a meteorologist at Météo Suivi Alsace explains: “It’s a real dust storm where the winds don’t exceed 50 km per hour. Some may be stronger, lifting garden furniture, but in Alsace we don’t have that volume yet.”

“It’s a very special phenomenon, because of the warming at ground level, when there is a lot of sun, and the air is very dry” Christoph Mertz, Atmo-Risk meteorologist details.

“The Earth is warming rapidly, but unevenly according to its occupation: between a plowed field, a barren land, and a meadow, there is not the same temperature. As a result, these small discrepancies lead to ground-level air circulation.” This type of vortex is formed “Rather in plowed fields, or desert areas (…) and when conditions are right, it grows. But as soon as it reaches a cooler surface, like grass, it disintegrates.”

On the other hand, a tornado is not the result of the same mechanisms at all. “It is a track, or trailing, of a storm cloud (…) that can last several minutes” Remember Florian Knoll. While the “dust demon”, is, “It can appear when the sky is blue” It is never malicious or very powerful.

dust demon “A fairly common phenomenon, even here in Alsace” thought Christoph Mertz, who has already published a study on this topic. This mentions several “dust demons” that were spotted and photographed in the area in April 2020.

This phenomenon may occur “April to September” says the meteorologist. Its appearance remains very local. brevity, From a few seconds to a few minutesmeans that there is not always a witness around, ready to be seen or photographed.

But the “Dust Devil” that formed on July 30 in Alsace-Possot was an impressive specimen, the size of “It’s not really common. It’s rare for tornadoes like this to happen.” Christoph Mertz confirms.

So if he knows that this kind of apparitions ‘Only in long dry spells, as it is now’, this “devil”, although not dangerous, is probably not so angelic. At least, this is one sign, among many others, that global warming is very real.

Or, as Matisse Grosnickel put it: “A dry, utterly scorched earth that has been set free. It is nature that sends a message.”

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