The winter floods of 2015/2016 in the UK - a review

A remarkably persistent and exceptionally mild cyclonic episode beginning in early-November 2015 and lasting around fourteen weeks brought severe, extensive and protracted flooding which impacted most damagingly on northern Britain, Northern Ireland and parts of Wales. Many existing rainfall and seasonal temperature records were eclipsed during this period and, most notably, maximum recorded river flows were exceeded over a substantial proportion of the country. At the national scale, previous maximum daily and monthly outflows were clearly eclipsed and four relatively discrete episodes of extreme runoff can be recognised. In many areas, the magnitude, persistence and repetitive nature of the flooding had major adverse impacts on communities, infrastructure, agriculture and a host of other sectors of the economy. The extent and duration of the flooding has very few close parallels in the historical record and, overall, it was a hydrometeorological episode which ranks alongside the 1975/1976 drought and 1947 floods as the most extreme broad-scale events captured in observational records during the last 100 years at least. The truly exceptional runoff patterns experienced in 1947 and 1976 had a major impact on flood and drought management strategies but occurred before the exacerbating impact of climate change was generally recognised. The 2015/2016 flooding, together with the impact of other protracted flood events in the 21st century thus far, has underlined the need to adapt engineering design and flood management strategies to accommodate the recent extension in the range of recorded runoff variability.