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 FGS or above umber of yellow 20 8 10 4 0 0 PR 15 MA 15 U 15 U 15 U 15 EP 15 OC 15 O 15 DEC 15 J 16 FEB 16 R 16 On time Late Actual Target 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 Potent 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.