In the Arctic, the weather plays a key role in determining how much ice covers the ocean. One weather phenomenon that has a significant influence on this is Arctic cyclones: they cause unusually warm and stormy conditions, which typically lead to a significant loss of ice. These conditions last for a particularly long time when several cyclones rapidly follow one another. An international research team led by the Alfred Wegener Institute has now, for the first time, systematically investigated the effects of these accumulating cyclones, using weather data from recent decades. In the journal Nature Communications, they have described this ‘cyclone clustering’ and its specific consequences for the future of sea ice and, by extension, the Arctic coastline.
‘Cyclone clustering’ occurs when several low-pressure systems rapidly pass through a particular area one after another, causing storms that are more severe and last longer than ‘normal’ storms. “In Europe, such events have frequently led to significant damage in the past due to high winds, heavy rainfall or high tide levels along the coast,” says Dr Lars Aue, lead author of the study from the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI).
To find out whether cyclone clustering also occurs in the Arctic and how these intense weather events affect Arctic sea ice, an international research team led by the AWI systematically analyzed and compared satellite and weather data from 1979 to 2024. “We adapted an algorithm for tracking weather systems so that it could detect rapidly consecutive cyclones in the Arctic,” explains Lars Aue. “We were then able to compare the state of the sea ice on satellite images before and after a cluster had passed through.”
The results show that, where cyclones coincide with Arctic sea ice, they break up the ice cover and cause ice floes to drift and collide. During the cold Arctic winter, the gaps that emerge as a result, normally refreeze within a few days. However, when a cluster of cyclones hits the sea ice, the persistent stormy conditions delay and hinder the gaps from closing again. During the warmer months, Arctic cyclone clusters are less intense, however, they can still have a significant local impact on the sea ice: they drive ice floes northwards and push them into the existing ice. This reduces the area over which the sea ice is spread. The storms also carry warm air with them, which thaws the ice from above, furthermore, they can also transport warmer seawater from deeper layers to the surface, causing the upper water masses to warm up. Over the last two decades, cyclones have thus contributed to ice loss, particularly towards the end of the melting season.
The number of storms that accumulate in a cyclone cluster varies depending on the region and the season, but averages 2.5 cyclones. Similarly, their impact also depends on when and where they occur. There are regions where the effect on sea ice is amplified by up to 1.5 times, and regions where the effect is amplified by up to 7 times. “On average across the entire Arctic, cyclone clusters reduce Arctic sea ice cover by about twice as much as conventional, isolated low-pressure systems. This condition also lasts about two and a half times longer,” says Lars Aue.
Another worrying finding of the study is that the loss of Arctic sea ice caused by cyclone clusters has increased significantly over recent decades. One reason for this is that the ice is losing its resilience to storms caused by cyclones, as it is becoming thinner and more mobile due to ongoing global warming. In summer, this could be further amplified by the increasingly warmer Arctic Ocean. “We could be entering a self-enforcing feedback loop: the weaker the sea ice becomes, the more cyclone clusters can reduce its extent, which in turn weakens the sea ice,” says Lars Aue. “Currently, we are using climate projections to investigate whether the intensification of the effects of cyclone clusters that we have seen in recent decades could continue in the future.”
The study highlights just how strongly weather events influence sea ice and how important it is that we understand the causes and effects of cyclone clusters in the Arctic. This is crucial, as coastal communities in the Arctic are increasingly exposed to dangerous weather events due to increasing cyclone activity: sea ice acts as a buffer against waves. Its retreat, combined with the increasing thawing of permafrost, is making coasts more vulnerable to storms. “Until now, there has been no systematic analysis of the impacts of cyclone clusters in the Arctic. With our work, we are filling a knowledge gap and lay an important foundation for projections that can depict the future of the Arctic sea ice - a central component of the global climate system - as accurate as possible.”
Original publication
Aue, L., Tiedeck, S., Finocchio, P. et al. On the relevance of serial cyclone clustering for Arctic sea ice. Nat Commun 17, 7847 (2026). https://doi.org/10.1038/s41467-026-76245-5
