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On this day in 2020: Storm Dennis hit the UK and Ireland

10:00
15 February 2024

On this day in 2020
Storm Dennis hit the UK and Ireland

Large wavesLarge crashing waves at the harbour of Porthcawl, Wales provided spectacular sights for locals, but preceded the full arrival of Storm Dennis which devastated the UK. - © picture alliance

On this day in 2020, Storm Dennis impacted the UK and Ireland, becoming one of the most damaging in years building upon the destruction brought a week prior by Storm Ciara.

Amid the two days the storm lasted over land on February 15th and 16th, Dennis delivered heavy rains and strong winds resulting in flooding across the entirety of the UK.

At the River Taff and Rhondda catchments in Wales, more than 160 mm of rain was recorded in a day, greater than their monthly rainfall average.

A weather station in Aberdaron also recorded wind gusts as strong as 91 mph, while 50 mph gusts were also recorded in Kent.

Major incidents were declared across England while south Wales experienced devastating flooding. At Dennis' peak 152 flood warnings were in effect across Wales, the highest number ever in force at one time.

River levels also rose to record highs with the River Taff at Pontypridd reaching its highest level for over 40 years, 80 cm higher than the historic flooding of 1979.

In total seven lives were known to have been lost as a result of Storm Dennis, with five in the UK.

Ireland largely avoided widespread damage from flooding, instead experiencing fierce gale-force winds leading to widespread power outages.

Dennis was named on February 11th 2020, while still situated over southern America. As the storm moved over the Atlantic it experienced explosive intensification becoming one of the most intense extratropical cyclones on record.

By February 17th, Dennis had moved on from the UK and impacted Europe before dissipating a day later.

Weather & Radar editorial team
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