Following a minor Sudden Stratospheric Warming (SSW) event in January, the Stratospheric Polar Vortex (SPV) has now recovered. Our forecasts for the coming week also suggest that conditions will become milder. So why does there continue to be speculation that cold weather is on the way for the UK with snow and ice for many?
The latest forecasts are showing that a major SSW is now likely to take place. The recent minor SSW weakened the SPV and it’s now likely to collapse and reverse in the middle of February.
A major SSW often makes the jet stream meander more, which can lead to a large area of blocking high pressure over northern Europe, including the UK. This blocking high pressure can lead to cold, dry weather in the north of Europe, including the UK, with mild, wet and windy conditions more likely for southern areas of the continent. However, this is not always the case and impacts on UK weather can also be benign when an SSW occurs.
Prof Adam Scaife, Head of Long-Range Forecasting at the Met Office, said: “There is now over 80% chance of a major SSW occurring. Although the impact will become clearer nearer the time, any effect on UK weather is most likely to occur in late February and March.”
Other factors can also impact the UKs weather in winter such as the Madden Julian Oscillation which is now also tracking towards a state that favours a cooler spell in late February.
In the meantime, it is important to remember that the occurrence of an SSW does not always equate to a ‘Beast from the East’ type scenario even though this happened in 2018. For example, in 2019, there was an SSW but little impact on the weather for the UK and NW Europe.
The current extended range forecast for mid-February suggests that the most likely scenario is for broadly changeable weather with westerly conditions and influxes of wind and rain at times, particularly in the northwest. Temperatures are likely to be around average through mid-February. We will be updating forecasts with a close view on late February and early March as the SSW unfolds.
This month we’re exploring the climate theme of ‘water security’. Water Security, as defined by the World Meteorological Organization (WMO), refers to ‘a population’s capacity to safeguard sustainable access to adequate quantities of acceptable quality water.’
At the Met Office, we work alongside organisations in the water sector to help support resilience and planning through the provision of weather and climate data and expertise. In this blog post, we’ll explore the link between climate change and water security and learn about some of the work that we have undertaken in this space.
Climate change and increasing heat drought events
In November 2022, the WMO published its first State of Global Water Resources report which assessed the effects of climate, environmental and societal change on water resources. At the time, WMO Secretary-General Professor Petteri Taalas said, “The impacts of climate change are often felt through water – more intense and frequent droughts, more extreme flooding, more erratic seasonal rainfall and accelerated melting of glaciers – with cascading effects on economies, ecosystems and all aspects of our daily lives. And yet, there is insufficient understanding of changes in the distribution, quantity, and quality of freshwater resources.”
As the climate continues to change as a result of greenhouse gas emissions, we are seeing increasingly hot, dry conditions in the UK and globally. 2022 has recently been confirmed as the hottest year on record for the UK with an annual average temperature of over 10°C, and this trend is projected to continue in the future. July 2022 saw the driest month since 1935 for England as a whole, and the driest on record for East Anglia, southeast and southern England, with the UK seeing just 56% of its average rainfall for the month. As a result, drought was declared by the Environment Agency in many parts of the UK in August 2022.
Impacts of drought on water security
Rising temperatures and increasing instances of drought events could have significant implications for water security. In 2020, the Environment Agency published a National Framework for Water Resources which showed that under the current trajectory, the amount of water available in England could be reduced by 10-15%, with some rivers seeing up to an 80% decrease in water during the summer months.
An Environment Agency spokesperson said: “Our climate is changing; the summer of 2022 demonstrates this. Action must be taken now, to ensure we are ready for managing droughts in the short term. As our National Framework for Water Resources shows, we need to develop new sustainable long-term supplies of water and for people and business to use water wisely to protect our precious water resources. In the short term the Government, Environment Agency, water companies, farmers, environmental and angling groups continue to work together through the National Drought Group to balance water needs and manage impacts if we experience prolonged dry weather again.”
How can we respond to threats to water security?
Climate change projections indicate that rainfall patterns in the UK will shift, which could present additional water security challenges to regional water providers. It is vital that water companies have access to the latest research, advice and accurate meteorological projections, so that they can effectively manage water supplies in their area.
The Met Office has been working with water company Anglian Water to support water resource management for the East Anglia region, one of the areas which is projected to be most affected by water scarcity.
By using novel approaches and new datasets, the Met Office worked alongside Anglian Water to strengthen their understanding of drought risk – both for today and for the future, in a warmer world. This improved understanding enables Anglian Water to enhance their resilience to future drought events.
Dr Joe Osborne is an Industry Consultancy Manager at the Met Office. He said:“As part of this work, the Met Office Industry Consultancy team has developed a statistical model to enhance Anglian Water’s understanding of extreme events. The model is used to generate 1,000 alternative realisations of a 105-year historical period (1914-2018), with daily outputs on a 5km grid over the region. The output validates rainfall and drought behaviour well, providing confidence in the suitability our datasets for future scenario planning.”
At the Met Office, we provide a range of weather and climate services to help support resilience, efficiency and forward planning for the water sector. This includes investigations into historical instances and future projections of drought, river flow analysis and consultancy around climate change projections. With meteorological expertise and knowledge of the latest advances in water resource planning, our consultants can help the water sector to mitigate the impact of weather and climate, adapt to changes and capitalise on the potential benefits of future weather events (for example, average increases in winter rainfall could improve resilience of supply with the appropriate resource management solutions).
Geoff Darch, Head of Supply Demand Strategy for Anglian Water concluded: “Understanding the investment decisions that are required to protect our customers against future weather and climate extremes is paramount. We need to make decisions based on robust and defendable science. Undertaking this challenging work with the Met Office means that data-driven investments are made where appropriate, ensuring that we better protect our customers and the environment we serve in the face of an ever-changing climate.”
The indications are that we could see some colder weather next week, but how cold and are we facing another Beast from the East?
It looks like we will start to see a change from the current mild conditions to a colder spell from the middle of next week (w/c 6th Feb), especially for parts of the south and east of England.
High pressure is expected to build and settle over or near to the south of the UK allowing colder air from continental Europe to cross the country. This high-pressure system will act to block the predominantly wet and windy weather from the Atlantic from crossing the UK, resulting in a spell of dry and more settled weather. The north and west of the UK is more likely to retain milder conditions and stay relatively unsettled.
It is most likely this cold spell will be typical of early February, with some frosty nights and colder days, but with daytime temperatures in mid or low single figures, lowest in the south and east.
However, there is a small chance – around 15% – that we may see an even colder, longer-lasting, and more widespread spell of very cold weather with the possibility of some impacts from wintry weather. This scenario is dependent on just where the high-pressure settles in relation to the UK.
At the moment, it looks we will see a gradual return, within just a few days, to milder conditions as wet and windy weather pushes across the country from the north and west. However, if the colder scenario does develop, the return to milder and unsettled weather could be slower for the south and east of the UK.
2023 has started with a January of marked contrasts, which has resulted in overall near-average figures for many of the UK’s weather statistics.
According to provisional Met Office figures, the one relatively consistent visitor was sunshine with England having its second sunniest January on record in a series which goes back to 1919. England had an average of 77.6 hours of sunshine, failing to top the record breaking 80.7 hours seen in January 2022.
The UK also had its third sunniest January on record, with an average of 63.1 hours of sunshine.
The month’s temperature figures were marginally warmer than average, with a period of mild weather at the start of the month followed by a cold spell. Later in the month, temperatures returned nearer to average, albeit with the north of the UK seeing the highest temperatures in the month.
Dyce, in Aberdeenshire, had January 2023’s highest temperature with 15.8°C on 24 January, though partly thanks to the Foehn effect, it’s not uncommon for Scotland to see the highest temperature recorded in a winter month.
Drumnadrochit, Inverness-shire, posted the lowest daily minimum temperature of the month, with –10.4°C the lowest temperatures got in January.
These contrasts helped to bring the UK mean temperature for January to 4.4°C, just 0.4°C above average.
The National Climate Information Centre Manager Dr Mark McCarthy said: “After a record-breaking 2022 for heat in the UK, January has started this year with a near-average month for temperature, which masks a period of cold weather in the middle of the month, as well as some mild weather at the start of the year.
“The month’s weather has largely been flipping from westerlies with milder air and rain to influxes of northerly air with cold and dry weather, which is not unusual for a UK winter. What this results in is fairly typical January temperature and rainfall statistics when averaged across the whole month.”
Similarly to the temperature figures, January 2023 saw near average rainfall for the UK with 125.7mm falling, 3% more than average.
Rain in January generally coincided with the mild air and a dominant westerly regime early in January.
Wales has seen 25% more rain than average, with 194.7mm falling in the month and England 9% more than average with 90.5mm.
Northern Ireland and Scotland both saw less rainfall than average, with 95.2mm (83% of average) and 171.5mm (96% of average) respectively.
Sun shines for January
January sunshine was in good supply, though not enough to trouble 2022’s record January sunshine figures for England.
The UK had its third sunniest January on record in a series which dates back to 1919, though much of the UK experienced a sunnier than average month.
Western and northern areas of Scotland got the least in the way of sunshine, with the Western Isles, a location not prone to January sunshine, having a fairly dull month, though not record-breaking.
In contrast, Berwickshire was one of a number of counties to see record levels of January sunshine, with many seeing more than 50% more sunshine hours than their averages for the month.
Dr Mark McCarthy continued: “One notable feature of January’s weather was the sunshine, with plenty of clear spells of weather, though not enough to trouble any national records.
“The far northwest might feel a little short-changed with sunshine duration, as well as western areas of Northern Ireland thanks to some more persistent cloud and rain moving in off the Atlantic in January.”
Provisional January 2023
Mean temp (°C)
Diff from avg (°C)
% of avg
% of avg
A typical winter so far
Two months into meteorological winter, the statistics are remarkably near average for rainfall and sunshine so far.
At this point in the season, you’d expect 68% of winter’s average rainfall and sunshine. At the conclusion of January, both of these are at 69%, though there have been obvious fluctuations, as is normal in a UK winter.
So far, there has been 236.7mm of rain for the UK in winter, though areas in the south of the UK have generally seen more rain compared to their averages.
During winter, rainfall and temperature can be closely linked, with wet weather generally linked to mild temperatures when Atlantic weather systems bring milder more unsettled conditions, and dry weather is associated with colder conditions when the UK is under the influence of air from the north or east.
During the period between 18th December and 15th January, the UK received over 162.6% of average Jan rainfall. During this time Wales received 212.6%. This was certainly a notably wet winter period, but not record breaking, and not as wet as equivalent spells in February 2020 or Jan 2016.
Winter so far has been slightly cooler than average for the UK with the mean temperature from December and January sitting at 3.6°C, which is 0.5°C cooler than average.
In this latest blog on our January climate theme of health, we explore the links between climate, air quality and our health. This blog has been written by Met Office scientists Steven Turnock, Fiona O’Connor, Paul Agnew and Matthew Hort.
A complicated, interconnected picture
Poor air quality is one of the leading environmental risk factors to human health, with an estimated 4 million annual premature mortalities worldwide and approximately 30,000 annual premature mortalities in the UK attributed to long-term exposure to outdoor air pollutants. Elevated concentrations of certain pollutants can also lead to other environmental impacts, including poor visibility, reduced crop yields and damage to buildings and vegetation. Poor air quality episodes can cover geographic areas from a single city to larger regions, and normally last from days to weeks.
Certain air pollutants (such as ozone (O3) and fine particulate matter (PM2.5)) are also ‘radiatively active’, which means they can influence the climate by providing additional warming or cooling. These pollutants are identified as short-lived climate forcers (SLCFs) because they reside in the atmosphere for a short period of time (less than 1 year), meaning their impact on climate is also shorter (within 2 decades) than long-lived greenhouse gases such as carbon-dioxide (CO2).
Our scientists have been analysing what the different future climate and air pollutant pathways mean for SLCFs and their impact on both climate and air quality. Our research shows that significant reductions in all air pollutants are beneficial to climate, air quality and human health, whereas there are some negative impacts on air quality and health across regions such as Africa if there are not future reductions in air pollutants. Therefore, it is important to consider the impact on air quality and health from future changes in these SLCFs.
Methane is another important SLCF. It is the second most important greenhouse gas after carbon-dioxide, albeit shorter lived in the atmosphere, and it contributes to poor air quality globally by forming ozone in the lower atmosphere. Efforts to control atmospheric methane may help to reduce the near-term future rate of warming, along with substantial reductions in surface ozone – providing clear climate and air quality benefits.
A pledge agreed at the 2021 United Nations Climate Change conference (COP26) to reduce global methane emissions from human activity by 30% from 2020 levels by 2030, has the potential to deliver benefits to climate, air quality and human health. Analysis from the United Nations Environment Programme’s Global Methane Assessment suggests that the 30% emissions’ reductions could result in 0.3°C of avoided warming over the next two decades.
Corresponding decreases in surface ozone could reduce premature deaths from poor air quality by over a quarter of a million and prevent more than half a million visits to accident and emergency departments from asthma globally every year. Using new methane modelling capability, the Met Office is working with partners in the UK academic community to quantify these outcomes. We will also assess how changes in emissions other than methane may affect the climate, air quality and health impacts.
Our local air quality forecasts
The Met Office produces a 5-day forecast of the Daily Air Quality Index (DAQI) for the UK. The DAQI is a representation of pollutant concentrations time-averaged throughout the day and gives an indication of overall air quality. The forecast is provided to Defra, as the government department responsible for air quality in the UK, for display on their website, and the data is also used in the Met Office weather app. The air quality forecast is made by combining a computer model for atmospheric chemistry and aerosols with recent observations from the Automatic Urban and Rural Network (AURN) of air pollution monitors. The observations are also used to check the accuracy of the forecast, as illustrated below.
Improving the understanding of air quality and health
The Met Office is involved in several research and development projects to improve our air quality forecast, and to further understand the links between air quality and human health. A core activity is the development of a new modelling framework which will permit an improved forecast resolution.
Another research topic, funded by the Clean Air Programme and delivered by the Met Office, concerns the production of a UK air quality ‘re-analysis’. This will use past observations and a modern computer model to provide estimates of hourly pollutant concentrations from 2003 to the present day for the whole of the UK. When compared alongside health records of the UK population, this new dataset has the potential to provide insight and improved understanding of the impacts of poor air quality on human health across different regions and following episodes of elevated pollution levels.
The future of air pollution and health
Poor air quality continues to be an important environmental issue, posing a considerable threat to our health both in the UK and around the world. The future direction of travel, in terms of human-induced emissions, could either worsen or improve this situation and have unintended consequences for climate. The Met Office is at the forefront of research that looks at improving our understanding of the interaction between health, air quality and climate. This will help us to make better predictions of air quality across a wide range of spatial (local to global) and temporal (days to decades) scales, enabling us to help people make better decisions to stay safe and thrive.
You may have heard speculation about a Sudden Stratospheric Warming (SSW) and that a ‘Beast from the East’ is on the way with freezing conditions and widespread snow.
Is there any truth behind the headlines and what can we say about the weather for the coming month?
Well, a sudden stratospheric warming is underway, but only a minor one. The warming is expected to peak towards the end of January. The strong westerly winds high over the Arctic, called the stratospheric polar vortex, have weakened and the vortex is partially collapsing. However, the polar vortex has been unusually strong so far this year and although there has been a minor SSW, the winds are expected to rebound quickly, recovering to speeds around normal for the time of year.
It can take a week or more for any impacts from an SSW to work its way down through the atmosphere and to have any influence on the weather in the UK. However, not all SSWs lead to cold weather and widespread snow for the UK, for example, the SSW in February 2018 led to the ‘beast from the east’ whereas the SSW in January 2019 had no significant impact for the UK weather, in fact, it stayed mild for the rest of the winter.
Forecasts at present show only minor impacts are expected and that other factors, such as La Nina and the Madden Julian Oscillation are also likely to influence our weather over the next few weeks. Our predominant weather is expected to come from the west with wet and windy periods. The unsettled conditions are expected to impact the north and west of the UK at the start of February as frontal systems push south across the country, weakening as they go with parts of the south remaining largely dry. Temperatures will stay around average for many.
Changeable weather is likely to continue through to the second half of the month bringing rainfall, heavy at times, again to the north and west. The south and east are expected to see some drier and brighter periods with some lighter rain. A brief spell of more settled conditions is possible in the middle of the period, bringing a greater risk of overnight frost and freezing fog, especially under clear skies with light winds. Temperatures are expected to be generally at or slightly above average, although a brief colder spell remains possible.
Not so long ago, we might have looked forward to a heatwave, particularly here in the UK – a chance to enjoy the sunshine and balmy evenings. Heatwaves, however, can cause a range of health problems. If you cannot find somewhere cool or off-load the excess heat from your body it can be very serious indeed and the extreme heat seen in recent years, such as the July 2022 heatwave, has resulted in a significant number of excess deaths.
Keeping cool is particularly problematic when the heat is ‘humid’. This is when the air contains lots of water vapour. High humidity makes it very hard for sweat to evaporate from our bodies which means that we cannot cool down. For people working outside or in overheating buildings, especially where the work is physically demanding, humid heat is a big problem. The world is getting warmer, and many places are also seeing increases in water vapour and the resulting humidity.
Researching exposure to high humidity and dry heat events
The distinction between humid heat and dry heat is a relatively new area of research. What we do know is that dry heat events can be much ‘hotter’ than humid heat events, and at present appear to be more lethal, or at least high temperature shows a stronger relationship with mortality than high humidity. However, humidity plays an important role in health and ‘productivity’. People ‘feel’ worse when the humidity is high and cannot maintain physical activity at the same level. This could mean slower progress in construction, lower yields for manual food harvesting or fewer completed tasks within a factory, which have economic as well as health impacts.
Climate change and heat health is the focus of some of the research being undertaken by the Weather and Climate Science for Services Partnership (WCSSP) programme, supported by the UK Government’s Newton Fund. A CSSP China project has been developing a global dataset of extreme wet bulb temperature (Tw) and air temperature (T) – HadISDH.extremes – that enables us to study the current level of exposure of regions to both high humidity heat events and dry heat events and measure the rate at which such events have increased in severity and frequency over the last 50 years. Wet bulb temperature is a common way of measuring humidity, is less complex than other measures of heat, and provides a critical threshold of 35°C beyond which the human body cannot survive for long. This is because human skin temperature is around 35°C. If the wet bulb temperature and skin temperature are both 35°C, sweating no longer works because the air next to the skin cannot hold any additional water and the body cannot cool down. In reality, even physically fit people struggle to undertake normal light activity when the wet bulb temperature gets within a few degrees of this threshold.
The HadISDH.extremes dataset allows us to identify those regions already experiencing very high wet bulb temperatures. Figure 1 shows that 31°C has already been reached several times over much of the tropics. This new dataset also allows us to investigate the two different types of events explicitly and explore what might be termed ‘stealth heat events’ where the air temperature might not be excessively high, but the wet bulb temperature is high enough to affect health and productivity.
Further global research
Other WCSSP programme research is also focused on heat health including:
Researching which weather patterns bring humid heat over China, a region where high humidity heat is commonplace already because the hottest season also tends to be the wettest. Climate change will make this worse;
Producing a global gridded dataset of ‘sector specific’ indices related to temperature such as ‘Heating Degree Days’, a ‘Warm Spell Duration Index’ and ‘Excess Heat Factor’;
Quantifying the current and future population exposed to high heat over Brazil, for present day and for a range of potential futures depending on future greenhouse gas emissions. This data has also been used globally;
Exploring the predictability of heatwaves and their corresponding impact on population relating to weather patterns over South Africa;
Investigating levels of solar and infrared radiation on people from surrounding building layout and fabric, which can significantly affect the heat impact in warm weather; and
Assessing the contribution of human-induced climate change to heatwaves and specific heat events, including how much more likely they become.
As our climate continues to change, research into health impacts will be critical to enable appropriate adaptation measures to be put in place. And by reducing emissions, we can minimise the worst impacts of climate change.
A landmark experiment is taking place in the Amazon Rainforest. Misha Khan from the Met Office International team explains what AmazonFACE is; why it’s so important and what it was like to visit the experiment site.
At the beginning of December, I had the opportunity to visit the AmazonFACE site in Manaus, Brazil. This current phase of the project is a partnership between leading climate scientists and organisations in Brazil from the National Institute for Amazon Research (INPA) and Unicamp University alongside scientists from the Met Office.
The project also collaborates with The Birmingham Institute of Forest Research (BIFoR), Exeter University and other world-leading consultants, and is funded by the UK’s Foreign, Commonwealth & Development Office (FCDO). More recently the Brazilian Government have provided a long-term funding commitment to the project.
AmazonFACE is a real-world climate experiment to build understanding of the Amazon rainforest’s response to environmental change. FACE – ‘Free- Air CO2 Enrichment’ – is an existing experimental method where controlled volumes of carbon-dioxide (CO2) are pumped into small areas of forests, crops or other ecosystems to simulate their response to climate change.
Taking place in different parts of the world including the UK and Australia, FACE has, until now, never been done at scale within a tropical forest environment, which is no doubt a huge undertaking. Scientists and experts are keen to experiment with FACE in Brazil as it is crucial to understand the Amazon rainforest’s response to climate change. The experiment seeks to develop understanding of lesser-known areas of climate science such as ‘how will the world’s largest tropical rainforest interact in the future with increased carbon-dioxide emissions in warmer, drier conditions?’
An awe-inspiring experience
I recently got the opportunity to visit the experiment site. During my week in Manaus, I met the team leading the project from INPA and Unicamp. The scientists have backgrounds in ecosystems, biogeochemistry and meteorology and shared their dreams from over ten years ago of building AmazonFACE. To finally see this come to fruition is inspiring.
The site can be found approximately 70 kilometres from Manaus, the capital of the state of Amazonas. The journey was smooth and straightforward, but I was told that this wasn’t the case up until a few weeks ago as the road turning to the site off the motorway was rather rocky and steep, adding an additional 50 minutes to the journey and slowing progress due to difficult access.
Thanks to funding for the project, the road has improved greatly – reducing arrival time to the site and improving health and safety. It will of course be crucial to ensure that the upgraded road does not encourage others to enter this area of forest and risk leading to deforestation.
As I stepped out of the car and into the Amazon rainforest, it felt as surreal as one can imagine. Feeling cool (in 33°C?!) as I was shaded under huge trees towering over me; observing beautiful species of fruits and plants I had never seen before; and hearing the sounds of animals and birds echoing through the forest!
It was only when I visited the site for AmazonFACE that I truly understood the immensity of the project and appreciated the effort it has taken. Huge concrete blocks carefully built to protect the forest floor and canopy surround a group of trees (those that will be observed) and in the centre of the ring is a 30-metre tower to aid scientists and researchers with their observations of the plants and trees within the parameters of the ring.
This forms one of the six rings of the FACE experiment and it is anticipated that all six rings will be in operation by the beginning of 2024. The installation process was taken with great care to minimise damage to the forest, with the towers being positioned with precision to avoid the removal of trees wherever possible.
The launch event
The INPA AmazonFACE launch event and site inauguration then followed. These were well attended by key funders and supporters of the project – Secretary Marcelo Morales, Ministry of Science, Technology and Innovation (MCTI), Melanie Hopkins (Deputy Ambassador to the UK, FCDO), Richard Ridout (UK Prosperity Counsellor) and Professor Richard Betts MBE (Met Office). Dr Richard Norby, Honorary Professor at the University of Birmingham, was also in attendance – Richard is recognised as the main authority in FACE systems in the world.
During the press interviews and speeches, Professor Richard Betts shared encouraging words, “AmazonFACE’s pioneering work will provide crucial new understanding of forest processes, which will help us to further improve Earth system models to provide improved estimates of the carbon balance to keep global warming well below 2°C.”
The overall tone of the two-day event was very positive. Senior attendees shared their excitement at seeing this phase of the project come to life, filling the AmazonFACE project team and scientists with happiness and pride which came through in their emotional speeches.
All collaborators are committed to working in partnership to complete the infrastructure build for the first pair of rings and control the level of CO2 in the canopy, plot the remaining four ring locations in the forest, and complete the site groundwork ready for another sixty-four, thirty-five-metre-tall towers and four tower cranes.
Whilst the remaining work is undertaken to complete the AmazonFACE site infrastructure, which is a pioneering experiment on its own, the scientific community are already planning the requirements to start the experimental research phase of the project, which will generate significant data helping to explore the answers to their questions.
I feel privileged to have visited the site and see it come to fruition and I would like to thank the wonderful AmazonFACE team and FCDO Brazil for their hospitality and time. I look forward to learning more about the project in the future!
In addition, record-high temperatures are being seen more frequently. Summer 2022 saw the UK record breaking a new all-time high of 40.3°C during a heatwave when 46 stations met or exceeded the previous national record of 38.7°C. With records highs, railways in the UK also have to endure sub-zero conditions in the winter, and even high-impact storms.
During Storm Eunice in February 2022 – which struck during a week of three named storms – cancellations on the rail network was at 44.1%.
The Office of Rail and Road (ORR) is the independent regulator responsible for safety monitoring on Britain’s railways; an area of the UK’s travel infrastructure that can be sensitive to variations in the weather.
ORR’s role for Britain’s railways involves working with train operators to ensure safety procedures are being followed and that people can get around safely on Britain’s trains, whatever the weather.
Paul Appleton is Deputy Director of Railway Safety at ORR and his team is busy working with operators through the winter season. He said: “Temperature range is a very interesting issue when it comes to the ability of Britain’s railways to run safely.
“At the cold end of the spectrum, the steel on our railways contracts, which can put them under massive tension and expose any underlying flaws. When it gets hotter, the steel expands and if it gets to extreme levels of heat then that expanding rail will risk buckling and possibly derailing a train.”
In 2022 temperature extremes weren’t hard to come by. The record maximum temperature of 40.3°C was recorded at Coningsby in July as part of a severe and widespread heatwave. At the other end of the scale, -17.3°C was the lowest temperature recorded in 2022, in Aberdeenshire in December. Train operators are often forced to impose speed restrictions to mitigate risks at either end of the spectrum.
Part of ORR’s remit is to ensure train operators have the processes in place to manage variations in temperature; something that can be traced back to selecting the type of steel used for Britain’s railways.
Paul said: “Rail temperature is very different to air temperature and there’s an operable range for steel railways. You can design your steel to work within a certain range, but you can’t extend that range. If you want the railways to be able to withstand 40°C summer heat, you’ll lose some of its reliability in lower temperatures during the cold winter months.”
As cold winter weather has come back into force in recent days, ORR’s focus has shifted towards low temperatures, snow, ice and the possibility of named storms.
“With snow, the problem is pretty obvious. If there is enough of it, it blocks the railway. With ice, there’s a risk of it forming on the 3rd rail which can prevent trains from drawing sufficient power,” said Paul.
Fortunately, rail operators, much like the public at large, take preventative action to mitigate the impacts of severe weather.
In the early hours of the morning, while much of the country is still sleeping, trains take to tracks all over the country clearing leaves from the line and de-icing the surface of the 3rd rail.
“Leaves on the line can be a big issue at this time of year. When trains run over leaves on a track, it creates a poor adhesion environment, where trains – which are obviously very heavy – struggle to get the friction required to move and stop efficiently.
“Just one way that risk is managed is with trains being sent out with high pressure jet washers to keep leaves off the line and ensure trains have the best possible contact with the track. This will often also include applying a substance to improve grip.”
According to Rail and Standards Board figures, poor adhesion costs the rail industry and wider society an estimated £355million every autumn. The Met Office works with many leaf adhesion services to help improve efficiencies throughout the year.
With steps taken to prepare railways ahead of severe weather, the public also have a role to play in keeping Britain’s railways running smoothly.
For ORR, a ‘severely disrupted day’ of rail travel is when cancellations are at 5% or more. During Storm Eunice on 18 February, that rate was at 44.1%.
Paul says the preparedness of the public for severe weather can help mitigate the disruption on days of severe weather.
“After a storm, debris on the line is one of the leading causes of ongoing disruption to rail services. Of course, some of this is down to fallen trees, but we also get a lot of garden furniture and trampolines on the tracks which all has to be dealt with before services can fully resume.
“Taking some time ahead of a storm to check for things that could be blown away would help and could also prevent delays on roads as well.
“If you’re looking to travel after a storm, take some time to check your train operator’s website to see if there are likely to be any issues. It’s thanks to the Met Office that they know when weather conditions will be impactful enough to disrupt operations, so do also check the Met Office website or App ahead of travel.”
The Met Office’s WeatherReady website brings together seasonal advice from expert partners to help you stay safe and make the most of the weather all year round. WeatherReady provides simple preparedness tips anyone can do to help them prepare ahead of severe weather.
Last week, Dr Debbie Hemming, Scientific Manager of the Met Office Vegetation-Climate Interactions (VCI) group, took part in filming and podcast recording for the Sky Climate Show on the subject of temperate rainforests. Here, Debbie explains why she is so interested in temperate rainforests and why they are an area of scientific research.
It might sound strange, but contrary to belief we do have rainforests here in the UK. Indeed, you don’t have to travel far from our Exeter HQ to find them. Nestled in isolated pockets along the moisture-laden west coasts of the UK and Ireland are fragments of lush ancient woodland that belong to the ecological group known as Coastal Temperate Rainforest.
Although these habitats occur in other locations around the world, they are limited to small, isolated pockets and are therefore considered rare and threatened by changes in climate, land use and associated impacts, such as wildfires or pests and diseases.
I was recently approached by Tom Heap from the Sky Climate Show who was interested to learn more about these fascinating ecosystems, why they are important and how they might be at risk from climate change.
We met at a spot almost right in the middle of Dartmoor on a suitably wet and windy morning and walked a short distance to find one of these magical locations.
Temperate rainforests are fascinating, diverse ecosystems. In the UK, they occur in isolated areas with at least 1,500mm of rainfall each year, although in Scotland this can be over 4,000 mm per year which is more than in many tropical rainforests. The ecosystems are characterised by oak trees, often stunted and contorted by the extreme conditions, interspersed with hazel, birch, rowan, ash and holly trees.
Covering everything in sight are vibrant green mosses and diverse lichen, which further support a community of ferns and other epiphytes. Various species of small animals, birds and insects are attracted to the benefits that these habitats provide. The abundance of mosses and lichen also indicate a requirement for clean air.
As well as being a landscape that can benefit wellbeing, temperate rainforest ecosystems provide us other services. By supporting flora and fauna that wouldn’t otherwise survive in these areas they increase the biodiversity of the region and provide a carbon sink that would not otherwise exist. They also play a role in flood control by slowing the transport of intense rainfall to the rivers.
However, with our changing climate and continued pressure on land use, the risks to temperate rainforests are likely to increase. We expect to see more weather and climate extremes as a consequence of our warming climate. Further hot, dry spells could threaten these habitats as they rely on high levels of rainfall and humidity to function. Increases in wildfires could also pose a risk to the small patches of land occupied by temperate rainforests.
It’s therefore important for scientists to understand the changes that climate extremes and trends are likely to have on temperate rainforests, and indeed other habitats around the world, in order to provide scientific advice to support their sustainable management into the future.