Providing Trusted Guidance to Help Protect Lives and Livelihoods from Flooding

Providing trusted guidance to help protect lives and livelihoods from flooding.

ANNUAL REVIEW 2015/16 Contents

Foreword 4

Overview of 2015/16 6

Performance 8

Key events 13

Improvement, development and learning 16

Customer insight 18

Forward look 19

We welcome your comments on any of the topics in this review.

Please contact us: Call: 0300 1234501 Email: [email protected]

2 3 Foreword

The Flood Forecasting Centre (FFC) is a highly in several reviews into the December 2015 successful working partnership between the floods. The complementary skills of our parent Environment Agency and Met Office. We forecast organisations were pooled to deliver this work for all natural types of flooding to provide as long – yet another excellent example of how we are a lead time to our customers as possible. We do better together. this by applying our skills in hydrometeorology in Our customer engagement work continues our jointly staffed centre to deliver operational to ensure we remain tuned in and sensitive services that we constantly strive to improve. to customer needs. We have had some great We are a key part of the national flood conversations about the possible look and feel of emergency response. a better service, particularly our flood guidance Supporting the emergency response community statement and strategic direction. This gives me to understand flood risk is very purposeful work the chance to express our gratitude to all of you and 2015/16 was another year when we saw the who shared your insights and helped develop our huge value in what the FFC does. Communities understanding. Unsurprisingly not everyone wants in the north of England were hit by two extreme or needs the same thing. Based on your feedback floods within 20 days in December. Just when we have shaped improvement plans ahead of the most people were preparing for Christmas coming winter and a clear strategic delivery plan our emergency responder customers and for the five years ahead. stakeholders were working shoulder to shoulder Central to our success is our people. We continue showing their clear commitment to do their very to develop and grow our staff. We have been very best to reduce flood impacts. active in the scientific community, connecting And what we experienced was record- with colleagues, learning from others and sharing breaking. The 24 hour rainfall total (341 what we have learned. millimetres recorded at Honister Pass in the Being trusted advisers is at the heart of all we Lake District) broke the 2009 record by close do at the FFC. One way we can maintain this to 10 per cent. There was so much water that trust is by verifying performance and sharing the design standards of some flood defence the data. I feel we have made particularly strong structures were exceeded – water flowed over progress in this area this year. We will use this schemes impacting lives and livelihoods. These improved understanding of performance to developments meant forecasting flood risk was plug gaps in our ability to forecast surface and very dynamic, underlining the importance of rapid groundwater flooding. communications with response partners. Flood forecasting is complex. Communicating This winter saw the deployment of temporary what we understand clearly to support action flood barriers to protect communities on a scale being taken is our goal. This review of 2015/16 that had not been experienced before. It was conveys our motivation and ambition to push a formidable logistical challenge supported by the boundaries and deliver ever better service accurate, timely flood forecasts. As collaboration in the times ahead. is at the core of our culture we worked with others to build scenarios – sharing what we knew and understood but also what we did not know. This supported contingencies to be planned. Once again these big floods provided rich opportunities to learn and clear signals of where we can improve. We were heavily involved Dr Crystal Moore Head of Centre, October 2016

4 5 Overview of 2015/16 floods

This is the third year in the last four when there has been prolonged seasonal flooding. The winter of Our analysis showed the following 2015/16 was the second wettest winter for 250 features of the flooding during this winter: years and produced 105 days of heightened flood • all sources of flooding – river, coastal/ risk. It started off quietly for the first half of the tidal, surface water and groundwater year. Then successive bands of heavy rainfall and – were experienced; the effects of ex-hurricane Kate in mid-November brought significant flooding across England and • there was widespread and locally Wales. River and surface water flooding affected significant and severe flooding; the north especially Cumbria and Lancashire. • the conditions included extreme rainfall There was also increased coastal flood risk to and also normal winter rainfall; Wales and south-west England from Storm Barney. • prolonged exceptionally high river flows By December many catchments in northern were recorded; England were saturated. Flooding occurred rapidly and for many communities in quick succession. • there was widespread flooding in rapidly Many rivers recorded their largest flows and responding catchments; highest levels resulting in severe impacts. The • temporary flood barriers were focus was again on the north of England and proactively used to reduce risk; Wales. On 5-6 December Storm Desmond brought rain on saturated ground, closely followed by Storm • some communities flooded several times. Eva (22 December) and further widespread rain over Christmas and Boxing Day. Together, these caused severe flooding across Lancashire, North, South and West Yorkshire, York, Leeds and Greater Manchester. Other parts of the north of England and Wales suffered from significant impacts. The increased threat of flooding continued right through January and February, as illustrated in Figure 1.

Figure 1: Flood Guidance Statement (FGS) forecast flood risk for 2015/16 – showing the highest risk level for each day.

6 7 Performance Timeliness

Our target is to publish the FGS so that it is received by our customers before 11am 95 per cent of the time, In our 2014/15 Annual Review we used our verification tool to produce performance data for the as this is an influential part of the daily flood forecasting rhythm to assist responders. The performance first time. This provided the template for future reporting. Our key operational activity statistics during 2015/16 for all FGSs at yellow, amber and red was 97 per cent (Figure 2). for 2015/16 are:

• 402 Flood Guidance Statements (FGSs) were issued including 30 outside of the usual 10.30 hour eness edition. The additional issues were mainly around Christmas with up to three FGSs on the Three month rolling average, yellow or above ﬁrst issue FGS busiest days. 100 0 • 67 Environment Agency and Met Office Incident Management Team telephone conference calls. • Chaired three National Flood Advisory (NFAS) calls with the Department for Environment, Food 0 36 and Rural Affairs (Defra), Cabinet Office, the Department for Communities and Local Government 0 32 (DCLG) and Welsh Government when flood risk escalated. 0 2 • Participated in 11 Lead Government Department briefings in support of Met Office and Environment Agency. 60 2 • Joined 34 Cobr meetings providing support and confidence to the ministers and the government. 50 20 • Regularly briefed the Defra Secretary of State and produced additional briefing 0 16 material throughout. 30 12 umber of yellow or above F or above umber of yellow 20

0 0 PR 15 15 U 15 U 15 U 15 EP 15 OC 15 O 15 DEC 15 16 FEB 16 R 16

On time ate ctual arget

Figure 2: 2015/16 FGS timeliness bar chart.

Recognising the importance of our flood guidance information we expect to deliver high levels of timeliness which can be maintained, particularly during busy periods when the FGS is a key decision-making document. We investigated the late FGS issues. IT problems and last minute changes to the final area of concern maps were the causes.

8 9 Accuracy and lead time Use of flood risk matrix

Our continued aim is to reliably provide timely and accurate flood forecasts to our customers with two To support responders to take the most appropriate decisions using the valuable lead time that our flood days lead time for surface water flooding, three days lead time for river, coastal/tidal and five days for forecasts provide, we are continuing to tick the flood risk matrix to indicate the specific forecast flood risk. groundwater flooding. This clearly and simply helps our customers see the likelihood and scale of potential flood impacts. We report our performance at county level for all FGSs issued at 10.30am, when significant and severe flood impacts were forecast. In 2015/16 during the prolonged periods of frontal rain during autumn and winter we exceeded our targets for accuracy in the prediction of surface water and river flood impacts (Figure 3).

Source Lead time Probability of detection Number of observations ✓ Leoo Surface water Day 2 69% 35

River Day 3 58% 47

Coastal \ tidal Day 3 N/A 0 otent ts

Groundwater Day 5 N/A 0 Figure 4: Example flood risk matrix from area of concern map.

Figure 3: 2015/16 probability of detection (POD) – flood forecast accuracy. Our performance analysis of how we use the flood risk matrix showed that during the winter of 2015/16 the severe column was not used at very low or low likelihood. The tendency was for us to move up the significant column rather than across to the severe column at lower likelihoods resulting in our overuse of Our probability of detection targets are 50 per cent for surface water with two days lead time and 40 per low/significant yellow. cent for river with three days lead time. Over 25 per cent of our FGS daily forecasts at significant or severe for surface water or river flooding were verified within the indicated area of concern map. One coastal forecast at significant or above was issued although these impacts did not occur. For those surface water and river flooding impacts positively verified as significant and above, our dominant lead time was Day 4, giving three days lead time. We have increased our targets for 2016/17 to help us drive through continuing improvements and ever higher performance levels.

Figure 5: Number of county forecasts and how our forecasts lie within the flood risk matrix.

10 11 Use of flood risk matrix (continued) Key events

Armed with this insight, we are keen to understand whether it is more useful to our customers if we forecast very low or low likelihood of severe flood impacts more often. Customers’ input to this 14-15 NOVEMBER 2015 discussion include: Early November brought the first storms of the winter period, which as part of the Name Our Storms project (see text box below) helped improve public awareness of adverse weather. "When the FGS was originally devised seven "We don’t move to severe often enough but years ago we weren’t doing the things we need confidence to be driven by forecasting Between Storm Abigail (10 November) and Storm Barney (17 November), the remnants of ex-hurricane do now – using temporary defences, moving science in the Environment Agency, Kate brought heavy rainfall to north-west England with 24 hours of persistent and widespread rain. 15 staff and equipment." Met Office and Flood Forecasting Centre." properties flooded, three schools closed, a caravan park was evacuated, roads were closed and there was significant travel disruption. At Seathwaite in Cumbria 241 mm of rain fell in 24 hours. While acknowledging that flooding occurred and high rainfall amounts were recorded in parts of Cumbria, the resulting flows in the larger rivers were relatively modest as catchment conditions preceding this storm were not yet saturated. There were also significant impacts for much of the north of England and North Wales. The FGS "There is a risk of crying wolf and losing "The biggest impacts are on our national gave three days lead time of the potential for severe flood impacts for Cumbria and two days for customers’ confidence. People need notice resources so longer lead time helps with the wider area. to move kit and people, and the FGS is being decision-making, but crying wolf if seen too used more strategically now. often. The Fire and Rescue Services need to shift equipment across counties so a couple De-escalation will always be a tricky thing. On of days is useful but the FGS would lose its balance the way the matrix is currently used Name Our Storms Project impact if severe used too often." is preferred for operational use." In 2015 the Met Office joined forces with Met Eireann, the Irish Met Service, to name wind storms that are expected to affect the UK and Ireland. It provides a single, authoritative system to help communicate severe weather, ultimately helping the It is clear that analysing our performance is public to keep themselves and their homes powerful in helping us gain insight into how our and businesses safe. customers use the flood guidance and lead time that we provide. We are using this knowledge and clearer understanding to help us drive further improvements. Figure 6: Area of concern map from FGS.

Carlisle, December 2015.

12 13 Key events (continued) Key events (continued)

4-6 DECEMBER 2015 26 DECEMBER 2015

A powerful Atlantic jet stream generated a very deep area of low pressure named as Storm Desmond. Further storms followed throughout December. Storm Eva, on 22 December, brought repeat flooding for This system developed rapidly scooping up warm air from the Azores, creating a conveyor of rain. There communities across Cumbria. A further area of low pressure moved across northern parts of the UK during were 38 hours of very heavy rainfall with exceptional accumulations setting a new 24 hour record of Christmas Day. This brought further misery across the north of England with severe flooding after 36 hours 341 mm at Honister and a new a 48 hour record of 405 mm at Thirlmere. Record peak flows were of widespread prolonged rain from Christmas Day morning right through Boxing Day. 109 mm of rain was recorded on several rivers, including the Eden and Lune in Cumbria and the Tyne in Northumberland. recorded in 24 hours in the West Pennines with Lancashire, North, South and West Yorkshire the worst River catchments across the north of England were now saturated with limited storage capacity for the affected. The river response was greatest in the Roch and Irwell catchments flowing westward off the rainfall, leading to a large amount of run-off and larger river responses compared to the November storms. Pennines and the Calder flowing eastward. Record highest flows were measured at several locations on The maximum daily flow on the River Eden on 6 December 2015 is a record for the UK (in a series from the River Calder. Exceptional flows in upland rivers were translated into particularly high levels in the Ouse 1980). River and surface water flooding affected around 7,400 properties mainly in Cumbria, transport through York and the Aire through Leeds. Approximately 9,050 properties were reported as flooded during was severely disrupted and 55,000 homes and businesses were left without power. The FGS highlighted the post-Christmas period, many of these in York and Leeds. The FGS had forecast significant impacts with significant river and surface water impacts with three days lead time then escalated to severe impacts five days lead time escalating to severe on Boxing Day. with high likelihood (red) on 5 December.

Appleby, 5 December 2015.

Equipment to repair Foss Barrier being delivered by helicopter, 28 December 2015.

Figure 7. Weather radar from 27 December 2015 showing 37 hour rainfall accumulations. Of note are the particularly widespread rainfall totals of over 100 mm.

14 15 Improvement, development and learning Flood reviews

We continue to have a buoyant programme of improvement projects in progress and planned for the We worked closely with the authors of the National Floods Resilience Review. This involved several in future, which we have focussed in light of tighter budgets. These initiatives aim to provide benefit in three depth sessions to scrutinise what happened when. We provided detailed information and evidence to distinct areas: the review, and supported the generation of new plausible extreme rainfall and flooding scenarios to test the Environment Agency Extreme Flood Outlines. The output was published in September 2016. • Improving our basic forecasting ability across all sources of flooding. At the same time there was a focus on the communication of forecasts through the end-to-end • Developing tools to provide objective assessments of forecast confidence. forecasting chain. This analysis was carried out by the Defence Science and Technology Laboratory (Dstl) • Continuing to develop and refresh guidance products to support strategic decision-making. Defence and Security Analysis on behalf of the Met Office and Environment Agency. The report was published in July 2016. Key work during 2015/16 included: Groundwater flood forecasting pilot: We took the first step towards developing a national groundwater flood forecasting capability with the successful completion of a pilot project with Learning from winter 2015/16 specialist contractor ESI Consulting. Surface water flooding hazard impact model: Hazard impact models forecast the likelihood of a hazard occurring (in this case, surface water flooding), identify the receptors (property, infrastructure As well as working with official reviewers we have made every effort to capture and learn from our etc) exposed to this hazard and, through an assessment of the vulnerability of each group of experiences of the Winter 2015/16 floods. These include: receptors, provide a forecast of overall impact. A surface water flooding hazard impact model has been developed, for trial within the FFC. This novel approach makes great use of existing datasets • Working closely with the Environment Agency to improve our maps and graphics. These provide and brings together colleagues from the Natural Hazards Partnership with contributions from Kings important visual images of forecasts and assist in flood scenario and major incident planning. College London and JBA Consulting. • Developing a robust process for early escalation in situations when severe impacts are forecast. Six-day river flow ensemble forecast: Understanding the confidence we have in the forecast models This uses our analysis of the patterns of progression through the flood risk matrix and feedback that inform our assessment of flood risk is critically important. Through developing high resolution from customers. ensemble forecasts at a scale compatible with UK river sized catchments we can now get a better insight into this. These forecasts were introduced just prior to the early December 2015 flooding in • Reviewing and updating the skills and resilience of our forecasters and duty managers including Cumbria and learning from this will help us embed their use into our procedures later in 2016. improving how we communicate confidence in the hydrometeorology assessments that drive our flood forecasts.

• Producing an updated glossary of flood forecasting terms to help us be more consistent and clear with our customers, particularly on the language for risk, uncertainty and scenario planning.

Figure 8. G2G, spatial gridded output using downscaled • Ensuring our decision making framework takes account of forecasting requirements identified MOGREPS-G ensemble, showing members greater in Environment Agency Major Incident Plans for example deployment of temporary barriers. than 50 year forecast for a 24 hour forecast for Saturday evening, 5 December 2015.

Coastal wave forecasting: To complement our coastal forecasting we have extended our capability by working with the Met Office to introduce seven-day wave ensembles. Waves, surge and wind are now being seen together in a single web-based system helping the team describe the expected confidence when forecasting these combined forces with greater clarity. FGS Next Generation: This ambitious project to improve the FGS made great strides during 2015/16. A series of customer workshops to fine tune requirements helped shape our user stories required for the tender process. This preparatory work subsequently enabled the successful supplier to be in place in to start design work in June 2016. We are on track to deliver the improved FGS by the end of January 2017.

16 17 Customer insight Forward look

We have been reinforcing our relationships with our key customers through our Stakeholder User Group. This review of 2015/16 outlines our continued efforts to improve our products and services while offering We held two meetings of the group this year. high quality flood forecasting and guidance. Looking forward to next year we will keep to this theme with the benefit of confirmed Defra funding for a The first one was hosted at the Department of Communities and Local Government’s Bristol office where further three years. This will enable our continued partnership working to deliver the best value from the we focused on the development of the FFC next strategic delivery plan for 2016 to 2020. We joined forces collective capability of Environment Agency and Met Office through the Flood Forecasting Centre. with Local Resilience Co-ordinators from the south west to find out how they use the FGS and what else they need from us.

The second Stakeholder User Group meeting was courtesy of Network Rail at its Milton Keynes Our priorities for 2016/17: headquarters. It was a great opportunity to discuss our winter performance. We gained valuable • Delivering our next generation FGS in early 2017. It will include improved production tools and insight into the differing needs of our customers as we reported how we used the flood risk matrix (see processes for the FFC team plus enhanced FGS and registration system for customers. The project performance section). Our government stakeholders were keen to have as early notice as possible of will also improve FGS reach through Hazard Manager (Met Office), Resilience Direct (Cabinet potential severe flooding impacts even when the likelihood was very low, however responder customers Office) and direct to customers for use with their own GIS and map layer systems. We will provide were conscious of the difficulties of de-escalating and wary of de-sensitising the public if flood impacts supporting guides and information to enable users to update their procedures. were forecast but rarely happened. This type of conversation is important, particularly in helping us to ensure our customers get what they need from us. • Taking forward work to improve forecasting capability for earlier flagging of potential severe impacts. The FFC continues to be valuable source of information and we host a steady stream of visitors. In 2015/16 • Ensuring we have resilient and sustainable procedures and staffing for prolonged these visits included from Sonia Phippard, director general, Claire Moriarty, permanent secretary, Neil seasonal flooding. Hornby, deputy director of flood risk, Sarah Hendry, director of flood and water risk management and her flood emergencies and contingencies team, all from Defra; Dame Mary Keen a new Met Office board • Continuing our support to FFC team members for professional development. member; Brigadier Matt Holmes during his research in support of the government’s flood review and a wide range of overseas visitors.

We continued our engagement with the fire services by presenting to the fire service high volume pump tactical advisers on their Continuing Professional Development training. We joined and contributed to the Environment Agency national duty manager training sessions. We took an exhibition stand and presented at Flood & Coast 2016.

York, December 2015.

We welcome your comments on any of the topics in this review.

Please contact us: Call: 0300 1234501 Email: [email protected]

18 19 Flood Forecasting Centre Met Office FitzRoy Road Exeter, Devon EX1 3PB United Kingdom Call: 0300 1234501 Email: [email protected] Web: www.ffc-environment-agency.metoffice.gov.uk