Storm Dennis hit several western European countries over the weekend with very heavy rain and hurricane-force winds. Minimum central air pressure of 920 hPa was recorded on Saturday, February 15, making it the second-strongest North Atlantic extratropical cyclone since records began more than 150 years ago; just 7 hPa short of the all-time North Atlantic record, set by the Braer Storm of 1993.
The storm left at least 2 people dead in the United Kingdom, dumped more than a month's worth of rain on South Wales, prompted the UK Environment Agency to issue a record number of flood warnings for one day, and caused widespread severe flooding across parts of the country. A yellow wind warning was still in place across the north and west of the UK on Monday, February 17. It also affected Belgium, Netherlands, Germany, northern Spain, and France.
Dennis caused huge waves and hurricane-force winds, with wind gusts in Iceland reaching 256 km/h (159 mph) on Friday.
The average wave heights in the North Atlantic were around 12 to 18 m (40 to 60 feet), but the largest waves easily topped 30 m (100 feet).
In South Wales, winds of more than 150 km/h (90 moh) were registered in Aberdaron, while more than 127 mm (5 inches) of rain fell which was a little more than what the area usually receives for the whole month of February. This resulted in flooding that prompted numerous evacuations, even cutting off several communities.
The government's weather agency issued a rare red warning due to the risk of "significant impacts from flooding", and "danger to life from fast-flowing water, extensive flooding to property, and road closures."
A 60-year-old man was found dead after falling into the River Tawe on Sunday morning, although the authorities clarified that it was not "linked to the adverse weather".
Dramatic footage also emerged showing a landslide sweeping down a mountain in Tylorstown.
In England, the storm was blamed for two fatalities who were retrieved from the sea in separate search operations off the country's southeastern coast on Saturday, February 15.
At one point on Sunday, England had 594 warnings-- the most flood warnings and lower-level alerts in place than on any other day on record.
Major incidents were declared in several areas in the country as the government deployed the army to deal with the impact of swollen rivers that cut off some communities.
Troops were in position in West Yorkshire, which suffered badly from flooding from last week's Storm Ciara.
"Our armed forces are always ready to support local authorities and communities whenever they need it," said defense minister Ben Wallace.
In France, the storm causes an onslaught of foamy surf across the streets. Disruptions were also reported on travel and power supply-- around 60 000 customers suffered from outages.
Two departments in the northwestern part of the country remained on an orange alert until Monday, according to Meteo France.
Impressionnante images de la Bretagne après le naufrage d'un cargo transportant du bain moussant. pic.twitter.com/BNGeNwSBeC— Nain Portekoi (@Nain_Portekoi) February 16, 2020
A yellow wind warning remains in place across the north and west of the UK on Monday morning, February 17, said the Met Office.
"It will be a windy, bright and [a] rather chilly start to Monday morning as Storm Dennis slowly clears to the east. There will be scattered blustery showers in the west too."
Travel delays are likely, as well as some short term loss of electricity and other services, the agency added.
Furthermore, flood-hit areas could still feel the impacts of the heavy downpour after it has passed. The Environment Agency advised citizens to remain vigilant as significant river and surface water inundations are expected to continue into next week.
"Storm Dennis will continue to bring disruptive weather into early next week, and there are flood warnings in place across much of England," said flood duty manager Caroline Douglass.
The mud covered village of Pentre in the Rhondda Valley after debris and flood water washed into the village from the hillside above. Copyright - Robert Melen. #stormdennis #photography #news #uknews #weather #rhondda #pentre #wales pic.twitter.com/i5kbEFMUz3— Robert Melen (@RobertMelen) February 16, 2020
Featured image credit: @BC_Gemma/Twitter