Storms Arriving in Clusters Are Speeding Up Arctic Sea Ice Loss, Study Finds

Arctic sea ice can usually recover from a single storm. But a new study finds that when several storms — low-pressure weather systems — sweep through the same region in rapid succession, a pattern called "cyclone clustering," they can keep ice gaps from closing and speed up ice loss. The research, led by the Alfred Wegener Institute (AWI) in Germany and published in Nature Communications, is the first systematic analysis of how these clusters affect Arctic sea ice.

Cyclones fracture the frozen surface and push ice floes into motion, making them drift and collide. In winter, the resulting gaps normally refreeze within several days, but a cluster of storms can prolong the disturbance and delay that refreezing. The storms can also carry warmer air that melts ice from above and stir up warmer water from below, heating the surface. Lead author Dr. Lars Aue and colleagues adapted an existing weather-tracking algorithm to detect rapidly consecutive Arctic cyclones, then compared satellite images of sea ice before and after each cluster, using records from 1979 to 2024.

A typical cluster involves about 2.5 storms, though the impact on ice varies widely by region — from 1.5 times the effect of a single storm in some places to seven times in others. Averaged across the Arctic, cyclone clusters cut sea ice cover roughly twice as much as an isolated storm, and the disturbance lasts about two and a half times longer. These losses have grown significantly in recent decades, likely because thinner, more mobile Arctic ice is less able to withstand repeated storms.

Aue said the findings raise the possibility of a feedback loop, in which weaker sea ice lets clusters reduce ice extent further, which then weakens the ice more. Researchers are now using climate projections to check whether this trend continues. Retreating sea ice already leaves Arctic coastlines more exposed to storm damage, since ice normally shields shorelines from waves.