Extreme Weather In Southern Germany June 2021

Peter Engelmann, July 3, 2021

2021: A cold spring with temperatures in May below average. Luckily there was lot of rain in parts of Germany after a drought since 2018 in some areas which damaged trees and raised serious concerns for example about the future of the water balance and water supply. In June a heat wave followed. However unlike in previous years there were no long lasting high pressure systems. The weather situation wasn’t so far stable for a long time. The heat wave ended with some extreme weather events. And again, we had situations for example in South-West-Germany or in Landshut, lower Bavaria, which were unprecedented. There are a lot of discussions now going on if this is climate-change related or if it is another rare weather pattern.

Things began to change in Bavaria June 20, 2021. The days before had been mostly dry except first thunderstorms in the Southwest and in the Alps. On June 20 there were some rumble and not so intense lightning in the region west of lake Ammersee. As usual there are huge local differences: There were soon stronger thunderstorm whereas a few kilometres apart from that place nothing or little happened. That’s very usual and always challenges weather forecasters.

Thunderstorm in the early evening hours of June 20:

Short lived thunderstorm cell June 20, 2021

The next days there was a much different weather situation: In the late afternoon or evening real strong thunderstorms occurred. Rotating supercell storms were also reported in the Southern Germany. Even more extreme weather happened in France where an air mass boundary created havoc. In France huge clusters of thunderstorms formed repeatedly and moved to Belgium and North-West Germany.

Strong thunderstorm on June 24, 6.45 p.m. near Diessen (Lake Ammersee, Upper Bavaria)

Thunderstorm approaching June 24, 2021

The extreme weather with strong thunderstorms, flash-floods, even extreme hail with enormous hailstones and masses of hail lasted for a couple of days. The reason: The air mass boundary moved only slowly in Europe. It worked like a machine charging up the atmosphere and creating new thunderstorms. A time-lapse video from June 21, 2021 late afternoon gives you some idea how quickly the storms formed:

It was interesting that there were very different types of thunderstorms. The location southwest of the Ammersee experience short-lived thunderstorms, a thunderstorm which arrived very quickly as the next day there was slow movement and plenty of time to take pictures. In the night there was also one of the “stroboscope”-like thunderstorms, where you hear not much loud thunder but you see an incredible light show with high rates of flashes. There were both thunderstorms without wind and thunderstorms with very strong wind.

The thunderstorm on June 24 created some great lightning:

Lightning June 24, 2021

The storm below occurred June 28, 2021 and brought intense lightning. However it was completely different as the “strobe-storm” the night before before. The lightning was also better visible. After one of the storms there was also a thick mist around sunset. Later the mist vanished and another thunderstorm with strong lightning occurred. The stronger storms came mostly from the Alps.

Thunderstorm in the evening of June 28, 10.00 p.m:

Lightning June 28. 2021

Flash Floods and Super Cell Storms

Finally there was an exchange of air mass. The hot humid air was replaced by colder air. June 29 was the climax of the series of thunderstorms in Germany: In Bavaria, a super-cell coming from Baden-Württemberg, intensified and brought an incredibly flash flood in Landshut Lower Bavaria. The days before a deadly tornado happened in the Czech republic. The video shows the aftermath of the big storm on June 29 which was accompanied by very strong winds.

Here is also an interesting thing for photographers and videographers: Usually most people are interested to catch a storm coming to them or before it happens. But there is a lot of possibilities to get interesting moods and pictures when the storm passed. The video belows shows what was going on in the atmosphere after this huge thunderstorm on June 29.

Thunderstorms before Sunset

In Upper Bavaria weather changed Sunday, June 28. Along the Allgäu Mountains, intense rainfall began in the afternoon. Thunderstorms with hail occurred in the south-east of Bavaria. The hailstorm pilots near Chiemsee started four times theses days. Clouds and rain created a magical atmosphere around Weissensee not far from the famous Neuschwanstein castle.

Three days later an impressing thunderstorm happened in the early evening hours in South-Bavaria. It was before sunset. Thus there were interesting effects with a colored sky. There were some intense local rainshowers and the weather lasted for more days.

On July 2 a supercell-storm devastated an area around Murnau, which is not far from Garmisch Partenkirchen. Witnesses reported that there was both hail and a flashflood rain at the same time. They could not remember a similar phenomenon happened before. Within 15 minutes streets were flooded and cows had to be rescued from a farm.

Later the week the weather calmed down. This kind of weather is very typical for the season in Bavaria. There is always a change between warm summer days and rain except the last years when a drought happened. Most of the severe storms in Germany happen in July. In 1984 an unparalleled hailstorm led to incredible destruction in Bavaria’s capital Munich.

Intense supercell-storms, hail and flash floods can, however, occur any time between May and September. In June 2019 a hailstorm led to a lot of destruction in the Northern-Ammersee region. In some years there were storms with flooding in May. Storms happen also in August, usually in September heavy thunderstorms are not so often because the days are getting shorter. There is less energy from the sunlight to generate these type of storms however there are weather patterns which could also lead to strong storms in October. In September 2017 lightning hit the Munich Octoberfest.

Thunderstorms with devastating hail happen more often in the south-east of Upper Bavaria rather than in the Allgäu. Usually, the storms develop over the hills and mountains in the West and move to the East. A squadron of Hailstorm pilots, “Hagelflieger” from Vogtareuth protects the area around lake Chiemsee efficiently and gather important scientific information.

June 2019: Dramatic Hailstorm put sailors in danger and a monster Heatwave.

May 2019 was the first month in Middle Europe for a long time which wasn’t too hot. There were some rainy days. It seemed that weather might turn in a more “normal” mode compared to 2018. This was before June. In the larger Munich area people experienced a freak hail storm on Whit Monday. There was also severe weather in other parts of Germany in the first half of June. Later the month, large parts of Europe suffered from one of the most extreme heatwaves ever recorded.

Aftermath of severe Hailstorm in Munich region

Thunderstorms and severe weather didn’t came unexpected on pentecost. Weather models showed a highly likelyhood for thunderstorms in the Alps and the Upper Bavaria region. However the events on June 10 proved again how tricky severe weather developments can be and how difficult it is to set precicely the right weather alert in motion.

Sunday, June 9, was more or less a qiet day. It was getting warmer in Upper Bavaria and other regions. There were already weather warnings issued. On Monday, June 10, the alert system of the huge lake Ammersee south-west of Munich was activated in the morning hours, but then it was quiet for most of the day. A lot of tourists enjoyed the holiday in Germany. People were swimming and sailing. Weather forecasters and and the lifeguard service were still expecting something to happen.




The weather radar showed signals getting stronger in the Allgäu and the Upland before the Alps around Kempten after noon. Here an incredibly strong cell was building up. When I checked the radar a couple of times in the early afternoon however, I couldn’t figure out which path that storm would take. I also didn’t figured out how fast this monsterstorm would move eastwards, so I was also surprised when it suddenly became really dark on this summer afternoon.

It was around 16.23pm when the orange alarm lights at the Bavarian lakes were activated again. There were still a lot of sailors out there. At one lake the lifeguard service warned people who were still swimming in the “Wörthsee” and closed the shore. 50 minutes later all hell brake loose on lake Ammersee. The Starnberger Merkur Newspaper later published a very interesting coverage.

Alex Beck, a sailor, told later the Merkur-reporters that the storm-cell was “racing”. Very soon the lifeguard service had to solve hands full over the next hours.

The same applied to firestarters and police: The thunderstorm left a path of destruction beginning in the Allgäu, hit several communities around the North side of the lake Ammersee region and also hit the west and the north of the Munich area.

Hailstorms in Upper Bavaria are not unusual. There is particularly a history for severe weather in May and around Pentecoste. What’s so unusual was the path, which was hard to predict. Big hail is often more seen in the South-East were there is even a special cloudseeding flyer unit for this problem. I didn’t find any report from a professional weather researcher, but I am sure this was a strong super-cell. Super-cells are more likely to take unusual paths.

The intensity was the other unusual fact. I experienced also strong wind gusts and smaller hail but 10 km to the north it was raining hailstones with the size of tennis balls.

Within minutes roofs very destroyed, nameless cars damaged, a motorway tunnel was set under water, greenhouses were completely destroyed and also a grocery store. It ended up in estimated damage cost of 30 Mio. Euros.

The same time people on the lake Ammersee were struggling for their lives. A couple hung on their capsized sailing boat, others were stranded and another sailor couple were only safed by their “persenning”, a cover, from the hail bombardement. They had reached a buoy but couldn’t leave their ship. Then they had to wait out the storm. At this time they experienced waves like never before according the their account in the “Starnberger Merkur” newspaper.

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Another thunderstorm in June

The following weeks people began to recover from the hailstorm, settling insurance matters and repairing windows, cars and houses. There were more thunderstorms but nothing like the cell on June 10. However another extreme weather situation was already throwing a shadow.

Weather models predicted an enormorous heatwave for the second half of June. Weather services were astonished by themselves about the numbers. And the models were mostly right. Germany saw new temperature records but not the 40 degrees Celsius. Nevertheless, there were set many new records. It didn’t took long and the bushfires, which were a problem in May started, again.

France saw the worst with some over 40 degree Celsius records. The authorities had to issue a state of emergency in some areas. Particularly Southern France was affected.

The situation calmed by the end of month. On July 1, 2019, a cold front with thunderstorms reached Southern Germany. There are still wildfires raging. The heatwave is only part of a problem which has the potential to become the real big threat for the near future: In wide parts of Germany there is still a drought. The government published recently a study about the effects of a drought lasting several years.

cold front and thunderstorms July 1, 2019

A Waterfall In The Sky: Thunderstorms In May And Fallstripes

May is often a time in the year of short-lived thunderstorms and some cooler rainy days in Middle Europe. However, since some years there is also more severe weather with flash floods and even tornados in May. 2018 had been particularly unusual with new temperature records in April. It was too dry in many areas and it still is. A big problem is that it seems that steady rain is missing more and more. Long lasting rain was a common weather pattern every year which wasn’t very amusing for tourists but important for nature and farming. That changed. As predicted by climate change researchers we have more showers and thunderstorm with extreme flooding now.

When I was younger I remember May not as a very warm month. In some years there was still a lot of snow in the mountains. Often it was very cold in the middle of the month. But this year it was more like midsummer rather than spring.

In Southern Germany, the dry period ended to a certain extent and more and more showers and thunderstorms happened.

The first thunderstorm in my area close to lake Ammersee in Upper Bavaria developed on early evening May 12.

It was very impressing because of the late sun which illuminated the clouds and rain at a low angle. May is a good time for taking pictures of thunderstorms because often the light is better as in July and the air is often more clear. Furthermore, it is a good time to photograph fall stripes of rain which look like curtains and can create very interesting patterns.

The following days more thunderstorms occurred. Weather forecasters had a tough time during May. A couple of time stable, warm weather was predicted. But weather doesn’t behave like it was supposed to be. On Pentecost, May20+21, it should have been warm and dry but there were thunderstorms and showers. May 20 indeed was a surprise, because that “summer day” was more or less a dark day with a heavy thunderstorm and flooding in a village between Murnau and Garmisch Partenkirchen. Already on May 18 an open-air event had to be cancelled due to a thunderstorm in Fürstenfeldbruck, a city not far from Munich.




This is what Sunday, May 20, happened: In the afternoon the sky was loaded with dark clouds and rain. There were also shrouds of mist surrounding the Hohen Peissenberg, which can be seen in the background. Some lightning could be seen in the South. In the evening the weather calmed down.

Morning, May 21, began with a misty sky. There was a low hanging layer of mist between the mountains an the lower areas. The mist soon disappeared and the sky became clear:
The air was still humid and the sun was hot. Perfect conditions for the development of further thunderstorms. In the late afternoon, a thunderstorm cell moved towards lake Ammersee. It was very interesting to follow this thunderstorm since there were fascinating patterns of fall stripes. Furthermore, there was also a rainbow.

It was remarkable that this year in May the thunderstorms were often moving in unusual directions. Sometimes there were moving from South-East to South-West or from North to South. Mostly weather systems are moving from West to East. An unusual constellation of pressure systems in Europe was one reason for the long dry period and the further development.

The thunderstorm on May 21 was coming closer for some time but then stopped. Perhaps the huge lake had an influence. It happens often that lakes are influencing local weather.

In this case, it was again good to know some viewpoints in the area before. It made it easier to follow the weather pattern.

The higher position was particularly helpful to see the rainbow which developed during the thunderstorm.

The rainbow was barely visible for some time but then intensified.

However the most special thing was the development in the upper part of the thunderstorm-cloud.

There were not only fall stripes below the cloud but in this case, it was clearly visible that rain came from the upper levels.

It was indeed like a “waterfall” in the sky.

The unstable weather continued.The title picture was taken a few days later, May 24.

There were further dramatic events in the middle of Germany with flooding. There was also a tremendous portion of hail in some places.
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