A red warning for wind, signalling “danger to life”, has been issued by the Met Office for parts of Wales and south-west England on Saturday as Storm Darragh hits the UK.
Gusts of 90mph (145km/h) or more were possible over the coasts and hills of west and south Wales, as well as funnelling through the Bristol Channel with some very large waves on exposed beaches, the forecaster said.
Warnings for possible significant flooding have been issued for parts of south Wales that were overwhelmed only last month during Storm Bert.
The rare red warning was due to be in place from 3am to 11am on Saturday and signalled a danger to life due to flying debris and falling trees.
Residents in the south-west of England and parts of Wales received a “severe alert” from the UK government on their phones through the public warning system on Friday evening.
Mobile phone users received the emergency alert on the home screen of their device, coupled with a vibration and a loud siren-like series of beeps.
“A red warning for wind has been issued in your area,” the alert said. “Stay indoors if you can. It is not safe to drive in these conditions.”
The emergency alert system was launched last year and is designed to be used for events such as severe flooding, fires or extreme weather. Similar systems had been credited with saving lives in countries including the Netherlands and Japan.
An amber warning for wind was already in place for large parts of the UK, with power cuts and flying debris possible amid the arrival of Storm Darragh, the fourth named storm of the season.
The amber warning for “potentially damaging” winds was in place on Saturday from 1am until 9pm for the west coast of the UK from South Ayrshire in Scotland down to Cornwall, as well as in Northern Ireland.
Yellow warnings for wind and rain on Thursday across parts of Northern Ireland, Wales, Scotland and England were extended to cover the north-east and south of England on Friday.
Flying debris could cause injury or danger to life and buildings may be damaged, such as tiles blown from roofs, the Met Office said. Power cuts and large waves should be expected, and some roads and bridges may be closed, with falling trees posing an additional hazard.
National Highways, which runs England’s motorways and busiest A-roads, has issued a severe weather alert for Saturday and has warned motorists in the south-west and north-west to prepare for gale-force winds.
It said routes likely to be affected by the strongest winds include the M5 in northern Somerset, the A30 in Cornwall and the M6 in Cheshire.
Severe winds were already affecting travel in parts of the UK with the M48 Severn Bridge in Gloucestershire closed on Thursday night because of gusty weather.
A yellow warning for rain will be in place for Northern Ireland and Wales, which were badly affected by flooding during Storm Bert, from 3pm on Friday until noon on Saturday.
Up to 60mm of rain could fall in these areas during the warning period, which might lead to some flooding and disruption, forecasters said.
Natural Resources Wales (NRW) has urged people to be vigilant and prepared for possible significant flooding in areas of south Wales on Saturday and into Sunday.
While rainfall totals are not expected to be as high as those experienced during Storm Bert last month, further heavy rain experienced in Wales this week means the ground is saturated and rivers could rise quickly, NRW said.
Some rivers will also contain debris yet to be removed following Storm Bert, which could heighten flood risk.
Rhondda Cynon Taf, where between 200 and 300 properties were flooded during Storm Bert, was forecast to be hit by heavy rain once again.
NRW issued more than 30 flood alerts and warnings, while the Environment Agency in England put more than 20 red flood warnings in place, with residents and business owners told to “act now”.
Simon Partridge, the senior forecaster for the Met Office, said there would be some “very dangerous” conditions, particularly around coastal areas.
He said: “Unless you really need to be going out in this on Saturday, it’s best to avoid it, particularly if you live in any of those areas covered by the amber wind warning … 70mph winds are dangerous and we could see, as the warnings suggest, a risk to life as a result.
“We have a very blustery spell of weather ahead. Amber warnings are usually over small areas, but because of the track of the storm, this will actually affect quite a large part of the UK.”
The warnings come as a result of areas of low pressure propelled towards Britain by the jet stream (a flow of winds high in the atmosphere). At the core of the jet stream, speeds are expected to reach 240mph, driven by cold air across the northern US and Canada.
Storm Darragh was named by the Met Office on Thursday morning. The names run in alphabetical order, starting this season with Ashley, Bert and Conall.
Last week, questions were raised over a lack of sufficient warnings of flooding after Storm Bert wreaked havoc in parts of south Wales and south-west England as a month of rain hit sodden towns and villages.
Extreme rainfall is more common and more intense because of human-caused climate breakdown across most of the world. This is because warmer air can hold more water vapour.
Flooding has most likely become more frequent and severe in these locations as a result, but is also affected by other factors, such as the existence of flood defences and land use.
• This article was amended on 6 December 2024. National Highways’ remit covers England only, not the whole of the UK as an earlier version said.
