January 23, 2025

expert reaction to Storm Éowyn

Scientists comment on Storm Eowyn, after weather warnings have been issued across the UK and Northern Ireland. 

Dr Ambrogio Volonté, Senior Research Fellow, Department of Meteorology, University of Reading, said:

“Storm Éowyn is shaping up to be an impressive storm, rapidly intensifying as it races east across the North Atlantic. ​ It is set to make landfall over Ireland in the early hours of Friday, before sweeping across the British Isles throughout the day.  Gusts are predicted to exceed 100mph in exposed areas on Ireland’s west coast.  Storm Éowyn could rival the ferocity of Storm Eunice and Storm Ciarán, both of which sadly claimed lives and left behind severe damage.

“The storm is “explosively developing,” meaning it’s intensifying at an exceptional rate.  Its central air pressure is expected to plummet by over 50hPa in just 24 hours – more than twice what’s needed for meteorologists to classify it as explosive.  This rapid strengthening happens when a powerful jet stream high in the atmosphere combines with a sharp contrast in temperatures and moisture at the ocean’s surface, creating the perfect conditions for the system to grow into a particularly intense and dangerous storm.

“In fact, Storm Éowyn’s structure mirrors some of the most formidable storms of recent decades, and its predicted intensity puts it firmly in the ranks of the strongest we’ve experienced.  With such extreme winds on the horizon, Met Éireann and the Met Office have issued important warnings so people can appropriately prepare for widespread disruption and damage.”

Prof Liz Bentley, Chief Executive, Royal Meteorological Society, said:

What do we know about this storm and is it expected to be damaging?

“Storm Éowyn is a rapidly deepening low pressure system developing to the west of the UK and will quickly move across the UK during Friday with peak wind gusts of 80-90mph across Northern Ireland, North Wales, Northern England and Southern Scotland and some exposed locations could record 100mph gusts.  These are damaging strength winds and there is a danger to life from flying debris, large waves near the coast, fallen trees and damage to building and the Met Office has issued rare red warnings.

What does a red warning mean?

“It is rare for the Met Office to issue red warnings.  They are the highest level of weather warning and indicate that dangerous weather is expected and there is a danger to life.  People living or travelling in the area under the red warnings are encouraged to take action to keep themselves and others safe from the impact of the severe weather, in the case of Storm Éowyn that impact is from strong winds.  In addition to the risk to life there is also the likelihood of substantial disruption to travel, energy supplies and damage to building and infrastructure.  People there should avoid travelling if at all possible and follow the advice of the emergency services and local authorities.

What causes storms like these?
“The jetstream, which is a band of strong winds at the top of the atmosphere around 30,000ft above the ground, provides the mechanism for storms, like Storm Éowyn, to develop.  The jetstream in winter is often stronger leading to more storms forming, and its position is often closer to the UK so those developing systems are directed towards our shores.

“The current maximum speed in the jetstream is more than 250mph and data from flightradar24 highlighted that a flight BA from Las Vegas to Heathrow hit a speed of 814mph thanks to the strong tailwind in the jetstream.  The subsonic speed record currently stands at 835mph, so that record could well be broken in the coming hours.

Is there anything unusual about this one or is it a standard winter storm?

“Storm Éowyn is a particularly potent storm particular because of a very active Jetstream, also the storm will be at its strongest as it crosses the UK and Ireland.”

Dr Jess Neumann, Associate Professor of Hydrology, University of Reading, said:

“Storm Éowyn is not one to underestimate – stay safe, stay prepared, and plan ahead.  This storm has the potential to bring serious risks, not just to travel and property, but to your safety and wellbeing.

“Storm Éowyn is set to hit the UK hard on Friday, bringing 90mph winds, torrential rain, and potentially leaving heavy snow in its wake.

“Expect widespread travel disruption, power outages and dangerous conditions along coastlines and high wind areas.  Severe flooding is likely, with heavy rain and snowmelt combining to create hazardous surface water and flash floods that could strike with little warning.  Check your flood risk online at https://www.gov.uk/check-flooding and take action now if you’re in a vulnerable area.

“If you must travel, be prepared for delays.  Carry spare warm clothes, blankets, bottled water, a torch, and ensure your vehicle is fuelled and well-maintained.  For those at risk of flooding, act quickly.  If time permits and it’s safe, turn off your gas and electricity, move valuables to higher ground, and relocate to safety.”

Prof Daniela Schmidt, Professor of Earth Sciences, University of Bristol, said:

“Climate changes is too often reduced to warming, and numbers which are small compared to the seasonal changes in temperature, giving a false sense of security.

“Climate change also changes how much vapour is in the atmosphere, how strong our storms become, how frequent they are, and how much flooding this has the potential to cause.

“We need to learn from disaster risk reduction to be better prepared for these events, and early warning is a very important part of this preparedness.  We need to look out for those most vulnerable, who might not hear these warnings, do not understand them, or cannot act.  And ultimately, we need to adapt and reduce our emissions as these storms, fires, droughts are just the beginning of we do not prioritise action.”

Prof Tim Palmer, Royal Society Research Professor Emeritus, University of Oxford, said:

“It may be tempting to attribute the exceptional Storm Eowyn to climate change.  However, in this case, it is not straightforward.  The storm has been fuelled by an exceptionally strong jet stream over the North Atlantic.  However, the strong jet stream is in turn linked to the circulations over North America which have brought cold temperatures over much of the continent, with a strong gradient of temperature with sea temperatures in the Gulf of Mexico (!) and elsewhere.  Whether the circulations bringing the cold air to North American have a climate change component is currently unknown.  Some speculate it does, but the evidence is not clear.

“Whilst climate change is relatively simple and straightforward at the global scale, it gets complicated at the regional scale where the effects of CO2 interact with the naturally occurring dynamical patterns of climate variability.  Although we have a good understanding of the basic thermodynamics of climate change – how it warms and moistens the atmosphere – our understanding of these dynamical impacts of climate change is much less good.

“It is likely that the thermodynamical effects of climate change have intensified Storm Eowyn somewhat.  However, we do not know whether the potentially more important dynamical effects of climate change have exacerbated the storm or not.  This is an area of ongoing research where the development of high-resolution climate models is proving vital.”

Declared interests

Prof Daniela Schmidt: “No competing interests.”

Prof Tim Palmer: “No interests to declare.”

For all other experts, no reply to our request for DOIs was received.