Storm Chandra brought extensive flooding across the island of Ireland yesterday, wreaking havoc on homes, businesses, transport networks and agricultural land.

The All Ireland Science Media Centre asked experts to comment on infrastructure resilience and adaptation, flood forecasting and preparedness, mental health impacts and public health concerns.

Dr Michael Bruen, Emeritus Professor of Environmental Hydrology, University College Dublin, comments:

Forecasting and flood protection

“These particular floods were driven by a relatively short period of extremely intense rainfall on ground already saturated from previous rain. Urban areas and newly developed areas are most vulnerable to that kind of event, as are larger steeper catchments downstream of steep slopes such as the upper Dodder, which flooded during Chandra.

“Some areas that have flooded in Storm Chandra have a history of flooding every 20 years or so, like in Enniscorthy and along the Slaney. So you’re looking at very, very extreme events occurring on the time scale of decades, so in between the events there’s a bit of memory loss as to what floods can do.

“As far as I’m aware, flood prone areas that have been protected, particularly along the Lower Dodder, have fared well during Storm Chandra. The challenge now is protecting areas that have not yet been protected, where the potential severity of flooding is well known and where there is infrastructure of significant value at risk.  

“We have the tools to forecast river flooding. Met Éireann provides rainfall forecasts, but the hydrological community has had models for more than 20 years that can estimate how high rivers are likely to rise in response to the forecasted rain. The estimates do have a degree of uncertainty, but can provide useful information for emergency management.

“Because of that, people should either have known, or should have been made aware, of the approximate levels rivers were expected to reach this time. So the level of surprise we saw did surprise me.

“There is a limit to what infrastructure alone can manage in extreme events. Beyond that, other measures are needed. The Office of Public Works has already carried out nationwide studies identifying flood-risk areas and categorising them by urgency. So the information exists, but implementation is complex. You are disturbing riverbeds and riverbanks, which brings environmental considerations, land ownership issues, hydraulic impacts, and changes to river flow regime. Examining all of these takes some time but must be prioritised.”

Declaration of interest: none received

Dr Sinéad Sheehan, Postdoctoral Researcher, School of Psychology, University of Galway, comments: 

Mental health impacts of extreme weather events

“As the harm caused by Storm Chandra, particularly in the eastern counties, continues to be assessed, the focus may be on damage to homes, businesses and items such as bedding or clothing that are considered essential. However, perhaps a more thorough assessment is needed with regards to the impact of extreme weather events on our health, including our mental health.

“Evidence suggests that experiencing an extreme weather event has the potential to be a source of trauma and distress, and this is the case, not only in countries that experience the worst effects of climate change, but even in Ireland, where, although the number of extreme weather events is increasing, the climate is temperate.

“As one might expect, the likelihood of experiencing distress or symptoms of trauma appears to be linked to the level of financial strain faced as a result of the weather event, but there are other considerations to take into account too. For example, young people appear to be particularly impacted by “eco-anxiety”, a term that describes a chronic fear of environmental doom, and while this is not a mental health condition in itself, it can be linked to anxiety, depression, insomnia and substance abuse.

“As we pick up the pieces after the storm, we should bear in mind that the harms caused by extreme weather events are not just physical, but psychological too.”

Declaration of interest: I declare no competing interests.

Dr Iris Möller, Professor of Geography & Trinity Coastal Research Group Lead, Trinity College Dublin, comments: 

Impacts and forecasting:

“Storm Chandra’s impacts are the result of a complex system in which atmosphere, land, and ocean connect in ways that challenge us. We know enough to be able to anticipate these impacts: we have river gauging stations, coastal buoys, and good weather forecasting.

“Where we fail is in putting that knowledge and data together for our benefit. For this we need a multi-agency approach. We need the meteorologists working seamlessly with river and coastal experts. We need systematic environmental observations and a better, integrated analysis of them to deliver location-specific targeted warning systems. We have the science and the technical ability to do this – but we need structural change to harness it.”

Preparedness and adaptation:

“The joint occurrence of sustained rainfall followed by a severe storm with easterly winds creating high waves on the Irish east coast was always something we knew would occur. We can improve our forecasting of these joint probabilities of events and we can better assist people in preparing for their eventuality. But we expect these types of events to increase in frequency and intensity under a changing climate and we know that we have exacerbated their impact through our interference in nature’s own way of regulating them.

“It is crystal clear that building on floodplains and on mobile coastal fringes of sand dunes, marshes, and beaches, has put people and infrastructure at unnecessary risk. It is time that we appreciate that nature itself, if left to function in its own way, can do the job for us: reduce wave energy through wide, spacious beaches, dunes, and wetlands and soak up rainwater, through grasslands and forests. What we now need urgently are the mechanisms to restore nature in places where we have destroyed it – we have the science but we need to support those who will need to make it happen. Strong political leadership, governance, and support for affected communities and their adaptation is what is needed.”

Declarations of interest: none received

Dr Paul Leahy, Head of Energy Engineering, University College Cork, comments:

Infrastructure resilience and climate adaptation

“Flood protection infrastructure such as embankments and drainage networks are designed to operate over decades-long lifespans and to handle extreme events. The issue is that extreme rainfall patterns are being influenced by climate change. Structures that gave sufficient protection thirty or forty years ago may not be suitable in today’s climate, as we are experiencing more frequent and more severe rainfall events. Climate model simulations project that these trends will continue in the coming decades. This means that current infrastructure needs to be re-evaluated and modified, and strategic planning needs to be informed by risks due to climate change.”

Flood forecasting and warning   

“In the shorter term, improvements in flood forecasting and warning can help communities to respond more quickly to extreme weather events. Unfortunately, no forecasting system is 100% accurate, but improvements in computing power in the past few years have allowed forecasters such as Met Eireann to give more localised forecasts, more accurate forecasts and to forecast further ahead”

Declarations of interest: none received

Dr Vikram Niranjan, Assistant Professor of Public Health, School of Medicine, University of Limerick, comments: 

Public health concerns

“Flooding from Storm Chandra could pose immediate and longer-term public health risks as an emergency that go beyond visible property damage. Flood waters are a mix of sewage, agricultural run-off, chemicals and debris, so direct contact should be avoided wherever possible.

“Key concerns include:

  • Gastrointestinal and skin infections from contaminated water, especially in children, older adults and people with existing health problems.
  • Damage to homes that leads to damp and mould, which can worsen asthma and other breathing problems and increase the risk of allergies.
  • Disruption of drinking water supplies, particularly private wells that have been submerged or discoloured; these should be considered unsafe until boiled or tested.
  • Occupational and recreational exposure to floodwater, which in some situations can increase the risk of infections passed from animals, such as leptospirosis.
  • The mental health impact of losing homes, possessions and a sense of safety, especially when storms and floods happen repeatedly.

“However, Ireland has a strong record of learning from previous major floods and improving how public health services respond. Over the past decade, clearer boil-water notices, stronger environmental monitoring and better coordination between health services, local authorities and community groups have helped protect people’s health during and after floods. We are now better prepared to issue timely health advice, support safer clean-up of homes and provide psychosocial support to affected communities”.

Declaration of interest: none received

Dr Eoin O’Neil, Professor in Environmental Policy and Director of UCD Earth Institute, comments:

Flood Risk Management

“There has been a programme of investment in flood defences over the past decade. However, Enniscorthy has yet to benefit from a flood relief scheme, and the community is now suffering the consequences of major river flooding.

“This reinforces the necessity of investing in climate adaptation measures, not just in flood defences, but also in non-structural projects like improved forecasting, awareness raising and, in some places, household level preparedness measures where community level defences will never be viable.”

Infrastructure Resilience

“Since the ‘big freeze’ of 2009/10, there has been a major focus on winter preparedness for our road infrastructure. The extended freeze at that time saw widespread road closures and severe salt shortages leaving many roads untreated. We subsequently saw speedy investment in new salt barns, nationally coordinated procurement and more attention to winter service plans.  

“The ‘Beast from the East’ in 2018, saw a combination of snow and windchill, and showed that the state’s planning and response had improved with proactive management. However the impact of Storm Éowyn last year exposed a lack of resilience in our energy infrastructure especially and we’ve been hearing since about where new investment should improve this for future severe storms events.

“In terms of Storm Chandra, the resilience of our transport infrastructure, road and rail, to cope with flooding is where we need more intense focus as storm and flood events will become more frequent and more disruptive. With future flooding, from river, sea or overland flow, we will need greater protection and maintenance of key assets like our motorways and coastal rail lines, as unanticipated closures do impose social and economic costs. We see the impacts of this on the N11, M50 and Wexford rail line this week. The lack of spare capacity in our transport system, particularly in and around Dublin, is really exposed when there is any deviation from normal weather conditions.”

Declaration of Interest: Eoin O’Neill is Professor in Environmental Policy and Director of UCD Earth Institute. He previously worked in flood risk management at the UK Environment Agency.

Dr Fiachra O’Loughlin, School of Civil Engineering, University College Dublin, comments: 

Infrastructure and preparedness

“The rainfall amount associated with Storm Chandra was significant. Just on the 27th of January alone, Phoenix Park experienced over 35 mm of rainfall and Dublin Airport experienced near 30 mm, this is an extremely large amount to fall in such a short period of time and most fell in the first half of the day. To put this into perspective, this is over 50% of the long term average rainfall that is expected to fall at either station. In addition, the past few months have been wetter than normal so the ground is completely saturated. Therefore there was little to no storage available, resulting in a number of rivers bursting their banks.

“Could we have been better prepared, were our flood defense sufficient? These are complex questions to answer. In Ireland, we are aware of the flood risk and there are a number of flood defense schemes being implemented across the country. However, the time taken to get approval and for the scheme to be built often is not fast enough to prevent these kinds of disasters. For example along the Dodder, phase two of a flood defense scheme was completed in 2023, up to Smurfit weirs near Clonskeagh but future phases are still at the design phase. This however, is of little benefit to those upstream who experienced flooding during Storm Chandra.

“However, it is important to note that it is impossible to reduce the risk of flooding to zero. Even if all communities were protected by flood defense schemes, these are designed for specific risk levels, often a one in a 100-year flood or an event that has a 1% chance of occurring in any given year. Larger events are possible and do occur.”

Declaration of interest: None

Dr Kristin Hadfield, Associate Professor, School of Psychology & Trinity Centre for Global Health, Trinity College Dublin, comments: 

Mental health impacts

“We can expect Storm Chandra to cause significant mental health challenges, with the extent to which it leads to anxiety, depression, and post-traumatic stress disorder depending on the severity of flooding, displacement from home, level of property damage, and how long daily life is disrupted. In the immediate aftermath, people often report sleep disruption, intrusive memories, irritability, difficulty concentrating, and acute stress. For some, distress persists for weeks or months, particularly where flooding is repeated or where there is ongoing uncertainty about the extent to which their home or business is protected against future flooding. The burden is often compounded by practical stressors: clean up and repairs, dealing with damp and mould, financial strain, and the time and paperwork involved in insurance and support schemes.

“Rapid, coordinated support and accessible emergency payments can reduce helplessness and support recovery. Flood defences should be viewed as a public health measure: reducing repeated exposure and restoring a sense of safety is an effective way to prevent chronic distress and the development of post-flood mental health problems in communities at risk of flooding.”

Declaration of interest: none received