Lothar’s Big Brother: the storm of March 1876

 “On the March 12, 1876, a cyclone travelling from west to east crossed [this] forest and toppled 100 000 trees in just a few hours …”. This text can be read on a commemorative plaque in front of a French royal hunting lodge in a forest north of Paris.

Not many European winter storms have ever been immortalised in such a fashion. This is a distinct sign of the havoc that must have been wrought on forests in Europe on that day. Given the economic importance of timber as a production material and energy source in the late 19th century, it is no surprise that highly detailed forestry damage reports have been published in the years after the event.

Why do we look back to 1876?

In the assessment of insurance losses from future severe storms in Europe, an analysis of major events in the late 19th century can prove just as useful as artificial scenarios arising from a weather or climate model. Such an approach also helps the insurance industry to gain a longer-term perspective on the sequence of strong storms that hit Europe at the end of the 20th century. Above all, we were interested in the question of what would happen if a storm of this magnitude took place today.

What happened in March 1876?

In mid-February 1876, the weather across Europe was already beginning to get unusually wet and windy with successive depressions sweeping in from the Atlantic. During the early hours of Sunday March 12, a small but very intense storm approached land from the southwest and barometers started to fall rapidly in southern Ireland and England. Lothar’s Big Brother was embarking on its path across Europe.

Why is the 1876 storm a reminiscent of Lothar in 1999?

Combining individual sources of indirect wind speed allows a pretty accurate reconstruction of the wind footprint on March 12, 1876. Despite many caveats in interpreting forest damage figures from the 19th century, the scope of loss is clearly reminiscent of that inflicted by storm Lothar in 1999. A variety of reports credibly substantiate that for the main regions affected, this was the worst event in the 19th and early 20th century. And the similarities to storm Lothar are striking, for instance in respect to the meteorological evolution, the minimum pressure reached and its tightly packed size. While storm Lothar was probably slightly more intense due to its more condensed structure and faster forward motion across Europe, the March 1876 storm affected a larger area thanks to its broader wind field.

If the 1876 storm happened today...

How high would the insured losses be if these events were to happen today? Based on an European Perils 2018 market portfolio, insured property losses alone would reach EUR 11 billion according to our estimates. All figures in the graphic are without the impact from post-event loss amplifications, which would actually drive up the losses.

Relative to the assets on the ground, Luxemburg and Belgium would be hit worst if there were a recurrence of the March 1876 storm today. France and Germany show more moderate relative loss levels, but remain the biggest contributors in absolute loss amounts. These resemble those inflicted by storms Lothar (1999) and Kyrill (2007) respectively.

The European market loss level of slightly above EUR 11 billion may appear surprisingly small in light of the storm severity described. However, this very intense storm spared major cities and passed through relatively thinly populated areas in France and Germany.

Had the same storm tracked only 75 km further north, losses in Germany and Belgium would have multiplied with severe damage inflicted on Antwerp, Brussels and the Ruhr region. The losses associated with such an extreme storm would stretch from infrastructural damage (property but also motor/inland marine…) over substantial forestry losses to business interruption for example due to power outages.

Would we be prepared for such a storm?

Evidently, the building structures and building codes today are very different to the ones present in 1876. Different to hurricanes, however, losses from European winter storms are driven by smaller "cumulative losses" rather than the complete destruction of a structure. This makes the preparation for such an event difficult even today.

Additionally, the areas of peak wind gusts are hard to predict, as they are very dependent on local surface conditions. This is why the exact track for a European winter storm is hard to pin down entirely.

Nevertheless, the weather forecast has continuously improved over the last decades. A 2015 Nature paper revealed that 3- to 10-day forecasts have been improving by about a day per decade — meaning a modern five-day forecast is as accurate as a three-day forecast 20 years ago, thus at the time of storms Lothar and Martin. This will give people nowadays more time to prepare for the impacts of a European winter storm compared to 1999.


Sources: Swiss Re publication: Winter storms in Europe: Messages from forgotten catastrophes
Bauer, P., Thorpe, A., & Brunet, G. (2015). The quiet revolution of numerical weather prediction. Nature, 525(7567), 47-55.)

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