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With low snow levels in the Alps, will we see another hot and dry summer?

Eylert Ellefsen
Archived blog post. This blog post has been transferred from our previous blogging platform. Links and images may not work as intended.


This blog post explores the current low hydrological balance across the Alp region this winter and what that could mean in the event of warmer weather this summer. Hydro reservoir levels this winter are even lower than last year, where we saw very low production levels and river flows during the heatwave which affected Europe. Through the study conducted by EQ we have concluded there is a probability of 20-25% of seeing a similar situation this year, given that the hydrological balance in the Alps for the end of February 2023 is lower than what we saw at the same period in 2022.

Review 2022

The hydropower situation across the Alpine region (including France, Switzerland, Austria and Italy) was extremely low through most of 2022, not only during the hot spells seen during the summer, which caused cooling problems for nuclear plants (France) and issues for coal transport (Germany).

The chart below shows the monthly productions statistics for the Alp region since 2016. 2022 clearly displays the lowest production levels throughout the entire year. Interestingly, 2023 has started at the same low level as last year.

For statistical purposes, we have displayed the yearly accumulated hydropower production for the Alps in the table below. This shows that hydro production for 2022 represented only 77% of normal levels, which is a deficit in real-terms of about 40 TWh. Whilst previous years have not deviated this far from the average, a longer-term view would reveal more years with production levels close to those seen in 2022.

The very low production seen by the time we reached summer last year was mainly a result of very dry weather from the start of Q2. This shown in the table below, which outlines a precipitation deficit of 25.9 TWh, and the according production deficit of –23.8 TWh.

Hotter than normal temperatures also caused increased evaporation, further making the situation worse. In France for example, the temperature during the summer was 2.5 – 3.0°C above normal.

These numbers clearly show the dependency between precipitation and production during summertime in the Alps. A combination of more precipitation during summer than winter, and rather low reservoir capacity explains this relationship (to a large extent). The hydrological balance by the end of Q1 will play a large part in defining the production situation, but precipitation conditions during the summer is normally the most important factor.

Outlooks for the spring and summer 2023

For the end of February 2023, we can see that the snow/groundwater situation and hydrological balance is in fact even worse than last year (displayed in the charts below). In fact, this year is the lowest since 2016 for both snow/ground and hydro balance.  

Furthermore, we see that the 2022 curve defined the minimum-curve throughout the year from March. So, with it being no wonder that the production for 2022 came out so low, will 2023 come out likewise?

Precipitation statistics – will 2023 be as bad as 2022?

We have extracted precipitation statistics for March-July to give an estimation of the probability to avoid a situation like we saw last year.  

Currently, the hydro balance for 2023 is about 5 TWh lower than 2022. In simple terms, at least 5 TWh more of precipitation until the end of July is now required in order for the production levels to come out higher than last year. In both the chart and table below, you can see the variation bands for accumulated precipitation across the Alps (period 1990-2021).  

The fifth percentile scenario at 43 TWh is around 5 TWh better than the 2022 scenario, but represents a severe low hydropower situation (most likely).

Looking at the accumulated precipitation statistics, it seems that about 50 TWh is needed before the end of July in order to avoid a similar situation to 2022. This means that by about 20%-25% probability the 2022-situation will be repeated this year.

We acknowledge that this a quite simplified evaluation, as the weather conditions between July and August will of course play a big part. However, we also notice the dry period during Q2 2022, so the accumulation effect of precipitation is obvious.

So, with a 20%-25% chance that we will experience a low hydropower level during the summer, low or moderate river flows during hot periods could easily cause a repeat of cooling problems for French nuclear plants or transport problems for coal in Germany.

When viewed in the current context of the winter drought in France and significantly lower river flows by nuclear plants than we saw at the end of February last year, EQ will continue to keep an eye on the situation and keep you updated as conditions develop.

Please contact EQ if you have questions about the German situation. You can contact us at

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