Home / Editor's Pick /

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
More on the topic
Weather map of Europe with high and low pressure areas marked. Isobar lines show the pressure distribution, alongside a forecast map. Different weather conditions from northern to Southern Europe.
Monday, 22 December 2025

"High over low"

Blocking weather conditions at Christmas
Tsunami damage
Friday, 26 December 2025

On this day...

The 2004 Boxing Day tsunami
Split image showing a family and children playing and sledding on a snowy field with winter hills on the left, and a UK weather forecast map on the right with sun and cloud icons, city temperatures, and cloud cover over northern Scotland, divided by a curved white line.
Wednesday, 24 December 2025

Unlikely this year

Defining a White Christmas
All weather news
This might also interest you
Split weather map showing the UK and Ireland. The left side illustrates strong winds circulating around a low-pressure system, with gusts of 20–30 mph highlighted in orange and yellow. The right side shows radar imagery with widespread blue rain bands and patches of thunderstorms, especially over northern England and Scotland.
Thursday, 28 August 2025

Breakfast brief

Remaining widely unsettled
Weather graphic showing rain and wind fields over the Canary Islands and a central warning symbol.
Friday, 12 December 2025

Storm and rain

Turbulent weather in the Canary Islands
Outline of Santa Claus with a yellow and white hat, "Ho-Ho-Ho" next to the outline above a Christmas tree.
Thursday, 25 December 2025

Merry Christmas!

Wishes from Weather & Radar
All articles
Weather & Radar

Weather & Radar is also available on

Google Play StoreApp Store

Company

Contact us Privacy Policy Legal info Accessibility statement

Services

Uploader

Socials

facebooktwittertikToklinkList