While Vereinigte Hagelversicherung VVaG reported 30,000 hectares damaged just a few days ago, this figure has more than doubled within a few days. A good 66,000 hectares were registered for regulation from June 18 to 25.
This is due to so-called supercells, which came from France through Baden-Württemberg and Bavaria to Austria and the Czech Republic, causing hailstorms over a length of several hundred kilometers. Local heavy rainfall with enormous amounts of rain from so-called "water bombs" and hailstones the size of tennis balls caused damage to almost all crops, often with total losses.
On June 22 and again on June 24, the damage area stretched from Lake Starnberg via Munich to Passau. In Baden-Württemberg, the Neckar-Alb region was hardest hit on June 21 and, just two days later, the strip from Freiburg via Reutlingen to Esslingen. A locally intense area of damage extended along the North Sea coast in the Groningen-Norden-Aurich triangle on both the Dutch and German sides of the border. In addition, abroad, the polder areas on the IJsselmeer and the Baltic region were particularly affected.
After the first surveys, Vereinigte Hagel now expects damage of about 20 to 23 million euros, a doubling compared to the beginning of last week.
Supercells and what they are about - currently no end in sight
The background to the now considerably higher damage figures are so-called supercells, which have a much higher damage potential than ordinary thunderstorms due to their rotation and longevity.
"Their most important feature is the so-called "mesocyclone," a powerful rotating updraft. It creates a negative pressure on the ground so that, like a vacuum cleaner, warm and energetic air can be constantly sucked in at the ground and reach the upper edge of the troposphere (above 10 km altitude). There the warm air is sucked in and there is also the danger of possible tornadoes. Subsequently, in the area of the sinking cold air, it is not uncommon for extreme downbursts to reach the hurricane range.
Over time, supercells develop a momentum of their own that prevents the sinking cold air (as compensation for the rising warm air) from entering the warm air area. Thus, the mesocyclone is fed with warm air for several hours. Due to the longevity and massive power of the rotating updraft, hailstones can be flung into the air several times, growing into large hailstones. From Monday through Thursday, conditions in southern Germany were ideal for these rotating monsters. A warm and humid air mass was stored in the lower atmosphere, so to speak the fuel for the engine of the rotating mesocyclones.
In addition, the wind near the ground came from an easterly to northeasterly direction (which favored suction), veered nearly 180° to the southwest up to an altitude of about 5 kilometers, and increased significantly. In short, there was sufficient directional and velocity shear. This is a basic requirement for the formation of rotation in the updraft region and helps to prevent the sinking cold air from reaching the front of the thunderstorm cell." (Source and more information at www.dwd.de on 6/27/2021 "Topic of the Day")
And it's set to continue. The DWD forecasts heavy thunderstorms in the south and southwest of Germany on Monday evening, as well as on Tuesday. Experts prepared for this, because in June or July such weather phenomena are not uncommon, as Vereinigte Hagel knows from almost 200 years of experience.
For more information:
Vereinigte Hagelversicherung VVaG
Wilhelmstraße 25
35392 Gießen
Tel.: +49 641 7968-0
Fax: +49 641 7968-222
Internet: vereinigte-hagel.de
E-Mail: info@vereinigte-hagel.de