Why doesn't it rain sometimes

Drought meteorologist"This is of course total stress for the vegetation"

April does what it wants, that is an old farmer's saying to describe the weather in April. Bright sunshine, followed by a shower of hail, a few minutes later then sunny again, the next few days of continuous rain. April was once characterized by its volatility.

It has been consistently dry and warm in Germany since the beginning of April. Rain fell only sporadically and locally. The result: In eastern Germany in particular, there are large areas that are already at risk of forest fires at the highest level. But the risk is also increasing in other parts of the country, for example 35 hectares of forest burned in the North Rhine-Westphalian community of Gummersbach 35 at the beginning of the week.

(pictrue alliance / dpa / Keystone / Urs Flueeler) Consequences of the drought: bark beetles
There is currently a lack of water not only in Saxon forests. Foresters use traps to monitor the enemy of the conifers, the bark beetle. Because if one tree is infested in one year, it could be 400 in the following year, fears Saxony's forest minister.

Why it is currently so dry and what consequences that can have, explained meteorologist Michaela Koschak in the Dlf.

Longer lasting weather conditions due to climate change

Ann-Kathrin Büüsker: Ms. Koschak, this constant weather situation for weeks now, how does it come about?

Michaela Koschak: We currently have a very, very strong and stable high pressure area in northern Europe, where the lows normally gradually run through. This is a so-called blocking high pressure area, which means the lows have to make a huge bend around us. This high remains and remains, it is sometimes replaced by a new one, but actually always in the same place. In other words, the Mediterranean is currently very changeable weather, a lot of low pressure areas, a lot of rain, and we are below this high and thus it remains dry, it is dry and will probably remain dry for a while.

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Büüsker: And why does this high remain so constant or is it replaced by new highs?

Koshak: These are these omega weather patterns, where the high pressure area really stays in place. Overall, due to climate change, we are already tending towards these longer-lasting weather conditions. For example, in February and the beginning of March, that was about six weeks, then we had one low pressure area after the other, it was more like these storm lows, this was the weather situation. We were lying in a valley of the so-called jet stream, that is a strong band of wind in the height, that is what makes our weather here in Central Europe.

And if that jet stream slows down a bit, which is now likely due to climate change, most scientists will agree because the temperature differences between the North Pole and the equator are no longer as great. Because climate change is a bit faster at the North Pole, so it gets warm faster here. And because of this slower jet stream, the weather conditions come in with us. We only had this low pressure situation at the end of February, beginning of March, now we have this high pressure situation and it stays and stays and stays.

(imago / Rene Traut) Rhineland-Palatinate: The risk of forest fires increases
The past two dry summers have also damaged the forest in Rhineland-Palatinate so much that many trees have died. The now dry wood could easily catch fire. The foresters hope for rain.

Büüsker: Does that mean that we have to say goodbye to this idea that April is very unstable in the long term and put the old peasant rule aside?

Koshak: You cant say it like that. In March we tend to have this changeable weather. The weather doesn't always stick to the calendar exactly, doesn't stick to the calendar, but sometimes it shifts a little. In the last few years we often had the stable weather conditions we have now in May. This year it has really just slipped into April, there is nothing really like April weather at the moment.

"We have to get used to more stable weather conditions"

Büüsker: It is often said that the weather is not the same as the climate, but if I understand you correctly, you would establish a concrete relationship between the current weather situation and the fundamental changes caused by climate change.

Koshak: Weather and climate is the big difference that we really have weather, that is what we have right now. You go out, this morning you can still feel this cool air, the cold wind, that's weather, we can feel that. From a statistical point of view, climate is the weather for at least 30 years. But of course we have been observing the weather for more than 30 years, and you can already see that it is changing.

It is getting warmer due to climate change, and this warmth also changes certain weather conditions than we had 30 years ago, for example. And so, yes, it seems we have to get used to the fact that we simply have longer, more stable weather conditions, sometimes drought, but sometimes also consistently changeable weather. This does not mean that it is only getting warmer and drier, but that there can also be a phase such as February or the beginning of March, when there is simply a lot of rain and a lot of wind.

Büüsker: What would have to happen in Germany now so that we actually get rain again?

Koshak: The high and low pressure areas would have to change their position a bit and of course low pressure areas would have to move towards us from the Atlantic. There are a few models: So the next few days will definitely be sunny and dry everywhere in Germany until Friday, some models now calculate a little bit of changes over the weekend that it will be more changeable, most models only from next Monday, which of course six days left.

So the whole thing is not yet certain, but at least it could rain from time to time. Unfortunately, the heavy rain, which the farmers especially want, is not in sight for the time being. That would be more like the showers, where there is rain with one, nothing happens with the other. From next Monday it could possibly rain a little here and there.

"Land rain would be the big solution"

Büüsker: Can we actually deduce something for the rest of the year from the weather conditions that we have seen so far this year? Many fear that we could have another year of drought like the last two years.

Koshak: You can't say that at all yet. That would be really charlatanism, there is nothing to be said about it. It is nice that it rained a bit in February and March so that the drought from last year could be dealt with a bit. However, now the soils are again very, very dry down to deeper layers, the rivers carry little water, and as I said, the risk of forest fires is very, very high. The wind that we still have in southern Germany yesterday, today and tomorrow is causing sandstorms. And especially if a fire has broken out: This wind kindles and spreads the fire even faster, the work by the fire brigade is made much more difficult by the wind. It's really uncomfortable at the moment, but of course you can't even look to the summer.

Büüsker: What does that mean for the ground when a rain shower comes on it?

Koshak: Of course that would really have to be this land rain, that is simply slow, permanent rain that falls for hours, then the ground could absorb it quite well. If a really heavy shower or thunderstorm just falls here and there, it can also be because the soil is so dry that it is simply drained off above ground - okay for the rivers, but not so good for the ground, of course . Land rain would be the big solution, but it is not in sight for the time being.

"Most of the time, nature creates a lot"

Büüsker: The fact that it is so dry in April of all times, April is actually an absolute spring month, so also a growth phase for many plants, if there is no rain, what does that mean for the vegetation?

Koshak: This is of course total stress for the vegetation. The forests notice it, of course the farmers and farmers, I think every allotment gardener has his garden hose permanently outside. This is of course very, very bad for the plants, if it got really cold again and really frost came in again, then it would be even worse. Fortunately, that's not the case at the moment, the days are behind us. But it is not ruled out that the Ice Saints will strike again. At the moment, the drought is the big problem for the trees. I think the winegrowers are not so unhappy about the sun, they are pretty good like last year, but everyone else really has to do with the drought.

Büüsker: Can nature make up for this rain, should it come now?

Koshak: It is hard to believe that nature is really very, very tough. Much will be able to be compensated for if it does rain at some point and not really rains for weeks or months like last summer. Most of the time nature creates a lot, I think we underestimate it a lot.

Statements by our interlocutors reflect their own views. Deutschlandfunk does not adopt statements made by its interlocutors in interviews and discussions as its own.