Storm Desmond was an extratropical cyclone and fourth named storm of the 2015–16 UK and Ireland windstorm season, notable for directing a plume of moist air, known as an atmospheric river,[1][10] which brought record amounts of orographic rainfall to upland areas of northern Atlantic Europe and subsequent major floods.

The extent of damage caused in such a short period across wide areas brought into focus the performance of UK central government flood defence strategies.

[14] The expected heavy rainfall was considered to be an extreme weather event by the Norwegian Meteorological Institute, who named it Synne.

[16] On 4 December, the Met Office issued a yellow warning for wind across most of the north of the UK, with gusts expected to reach 70 mph (110 km/h) in south-west Scotland.

Storm Desmond broke the United Kingdom's 24-hour rainfall record, with 341.4 mm (13.44 in) of rain falling in Honister Pass, Cumbria, on 5 December.

[22] Desmond created an atmospheric river in its wake, bringing in moist air from the Caribbean to the British Isles.

[23] In the Republic of Ireland, the worst affected areas were the province of Connacht and counties Donegal, Westmeath, Tipperary, Limerick, Clare, Cork and Kerry.

Millions of euro worth of damage was caused in Bandon, Fermoy, Kenmare and Tralee, while the Blackpool area of Cork city was severely affected by a higher level of water flow in the River Lee.

In Glaslough, County Monaghan, the body of a 70-year-old man was found when his car was believed to have become trapped in a dipped part of a flooded road.

[32] In Wales, heavy rainfall led to flooding close to Llandygai, near Bangor in Gwynedd, with RNLI coastguard helicopters rescuing one person from their car.

A 90-year-old man was killed after being blown into the side of a route 143 bus outside Finchley Central tube station in London by a sudden gust of wind around 12:35 GMT.

[36] In addition, over 2,000 homes were left without power in the Republic of Ireland as a result of Storm Desmond, mainly along the country's Atlantic west coast.

[33] Dozens of domestic, UK and international flights were cancelled at Dublin Airport on 5 December due to high winds, severely affecting carriers such as Aer Lingus and Ryanair.

A 200-year-old bridge in the Isle of Man collapsed amid severe flooding[44] A number of Scottish football fixtures scheduled for 5 December were postponed as a result of Desmond.

[48] Widespread flooding was expected after heavy rains on Boxing Day as a result of Storm Eva, with the Met Office issuing a red warning for parts of Cumbria, Lancashire and surrounding areas Expensive flood defence systems were proven ineffective and in some cases appeared to increase the problem.

Professor Dieter Helm, Chair of the UK government's Natural Capital Committee stated in January 2016: "Flooding crises tend to follow an established pattern.

The conventional approach to flood defence, carried out by the Environment Agency (EA), and financed largely by the Treasury, is at best inefficient.