Hurricanes form over warm ocean waters, making them unusual in Europe. The jet stream occasionally diverts hurricanes born in tropical Atlantic waters northwest, but they gradually fade as they reach colder waters. Stronger hurricanes reenergized by jet stream winds are twice as likely as weaker ones to cross the Atlantic and wreak havoc in Europe, according to new research.
Hurricanes in the Atlantic draw international attention due to the devastation they can cause across North America and the Caribbean. Just a few days ago, ex-hurricane Fiona made landfall in Canada as one of the strongest storms on record. These cyclones, while less well-known, can also cause havoc in Europe.
It has been unclear why some hurricanes make it to Europe as ex-hurricanes while others do not. The scientists investigated this question by studying 180 ex-hurricanes over a 40-year period, discovering that stronger hurricanes are far more likely to reach Europe, and that those encountering strong jet stream winds frequently reintensify, allowing them to move further east.
Our research shows stronger hurricanes, and hurricanes that are re-energized by the jet stream over the Atlantic, are far more likely to hit Europe. They appear to retain some recollection of their strength in the tropics.Elliott Sainsbury
The study, led by the University of Reading and the National Centre for Atmospheric Science and published in the American Meteorological Society journal Monthly Weather Review, helps explain why ex-hurricanes impact Europe, which is especially important because warmer ocean temperatures due to climate change are expected to make hurricanes stronger.
Elliott Sainsbury, a Ph.D. researcher at the University of Reading who led the study, said: “Ex-hurricanes are fairly rare in Europe but can be deadly and destructive events, making it very important that we better understand why they arrive from across the ocean.
“Our research shows stronger hurricanes, and hurricanes that are re-energized by the jet stream over the Atlantic, are far more likely to hit Europe. They appear to retain some recollection of their strength in the tropics.”
“We’ve now established a remarkably strong link between hurricane strength and rainfall. As stronger hurricanes become more common as a result of climate change, we may see more ex-hurricanes hit Europe in the future. However, there are other factors to consider, and more research into this question is required.”
Although cyclones are common in Europe, only about two ex-hurricanes arrive each year, usually between August and November. Ex-hurricanes, on the other hand, can bring extremely strong winds and heavy rainfall, with some of Europe’s strongest storms on record being ex-hurricanes.
Ex-hurricane Ophelia set a national wind speed record in Ireland in 2017 and killed three people, while ex-hurricane Katia caused more than £100 million in damage in Scotland in 2011.