Powerful hurricanes get a second wind in Europe

Stronger hurricanes that recover from jet stream winds are twice as likely to cross the Atlantic and wreak havoc in Europe than weaker ones, new research has found.

Atlantic hurricanes attract international attention because of the destruction they can cause in North America and the Caribbean. Just days ago, ex-Hurricane Fiona hit Canada as one of their strongest storms on record. Although less well known, these cyclones can also wreak havoc in Europe.

The question of why some hurricanes reach Europe as ex-hurricanes while others do not is unclear. Scientists investigated this question by studying 180 former hurricanes over a 40-year period, finding that stronger hurricanes were much more likely to reach Europe and that those that encountered strong jet streams often re-strengthened, helping them to move further east.

The study, led by the University of Reading and the National Center for Atmospheric Sciences and published today in the journal Monthly Weather Reviewhelps explain why ex-hurricanes affect Europe, which is particularly important as warmer ocean temperatures due to climate change are expected to make hurricanes stronger.

Elliott Sainsbury, Ph.D. a University of Reading researcher who led the study said: “Ex-hurricanes are quite rare in Europe, but they can be deadly and destructive events, making it very important to better understand why they arrive overseas.

“Our research shows that stronger hurricanes and hurricanes that are rekindled by the jet stream over the Atlantic Ocean are much more likely to hit Europe. They seem to retain some memory of their power in the tropics. We have already established this remarkably strong correlation with hurricane strength. As stronger hurricanes may become more common under climate change, we may also see more former hurricanes reaching Europe in the future. However, there are other factors to consider and more research is needed on this.”

Cyclones are common in Europe, but only about two ex-hurricanes reach the continent each year, usually between August and November. However, they can bring extremely strong winds and heavy rainfall, with some of the strongest storms recorded across Europe being ex-hurricanes.

Ex-Hurricane Ophelia set a national wind speed record and killed three people in Ireland in 2017, while Ex-Hurricane Katia caused more than £100m of damage in Scotland in 2011.

The study, published today, is the latest contribution from scientists at the University of Reading and the National Center for Atmospheric Sciences, who are working to understand the risks posed by ex-hurricanes to Europe.