A rare red warning for wind, which warns of significant disruption and a “danger to life”, has been issued by forecasters as Storm Darragh hits the UK.

The warning covers parts of Wales and the south-west of England, including Cardiff, Bristol and Devon, and is in place from 3am to 11am on Saturday.

The Met Office warns of “damaging winds”, with gusts of 90mph possible over the coasts and hills of west and south Wales.

Forecasters say the strongest winds will begin to ease from late morning.

A separate amber warning covering a larger swathe of the west coast of the UK, stretching from southern Scotland to Cornwall, and Northern Ireland is in place from 1am until 9pm.

Flying debris and falling trees could pose a risk to life, while large waves and beach material could be thrown on to coastal roads and seafronts.

There could also be damage to buildings and homes, with roofs blown off and power lines brought down, as well as power cuts affecting other services such as mobile phone coverage.

Roads, bridges and railway lines may be closed, with delays and cancellations likely to bus, train and ferry services and flights.

The fourth named storm of the season is also expected to bring heavy rain over the weekend, with more than 100 flood warnings and alerts in place across the UK.

An amber warning for rain is in place in Wales from 3am to 6pm on Saturday with heavy rain likely to lead to disruption to transport and infrastructure.

Periods of heavy rain in south and mid-Wales through Saturday will likely see 20-30mm of rain fall in three to six hours, with totals of 80-90mm possible by the time rain begins to ease in the evening.

Welsh Deputy First Minister Huw Irranca-Davies has warned there may be very significant impacts from the storm and urged people to take extreme care this weekend.

“Red warnings are issued when there is a potential threat to life, and therefore it is essential that people in Wales heed the warnings and take very great care if they are travelling on Saturday,” he said.

“Welsh local authorities, emergency services and Natural Resources Wales have activated their preparedness structures in readiness for Storm Darragh. I urge people to make sure they are aware of the warning levels for their local area and to follow all official advice.”

Stena Line said the storm would be “impacting” some sailings over the coming days, and Bristol Airport said disruption is expected.

National Rail said the storm is likely to affect services across the whole network, advising people to check their journey in full before travelling as it may mean last services of the day are cancelled and passengers may not reach their destination.

A yellow warning for rain is in place for Northern Ireland and Wales, which were badly affected by flooding during Storm Bert, as well as parts of Scotland from 3pm on Friday until noon on Saturday.

Up to 60mm of rain could fall in these areas, which may lead to some flooding and disruption, forecasters said.

Rhondda Cynon Taf, where between 200 and 300 properties were flooded during Storm Bert last month, is set to be hit by heavy rain once again.

Met Office chief forecaster Jason Kelly said on Friday: “The worst impacts from Storm Darragh will be felt as we go through the early hours of tomorrow morning and throughout Saturday with, in addition to the broad yellow warning, red and amber wind warnings in place from 1am tomorrow.

“In the red warning area, we could see wind gusts of up to 90mph along the coasts of west and south Wales as well as funnelling through the Bristol Channel, with some very large waves on exposed beaches.”

Drivers are encouraged to postpone journeys and park well away from large trees.

RAC Breakdown spokeswoman Alice Simpson said: “A red weather warning is highly unusual and should be heeded as it can indicate a risk to life.

“With parts of Wales and the South West set to be battered by the wind between 3am and 11am on Saturday, we strongly advise drivers to postpone their journeys if they can.”

Meanwhile, Longleat Safari Park in Wiltshire said on its website it will not open on Saturday due to the storm for safety reasons.

In racing, Sandown’s Betfair Tingle Creek Chase meeting and the Boylesports Becher Chase fixture at Aintree on Saturday must pass precautionary inspections due to the threat of high winds.

Belfast City Council said on its website that the city’s Christmas market will stay closed on Saturday due to the weather warnings while the Enchanted Winter Garden events at Antrim Castle Gardens have been cancelled for Friday and Saturday.

The Environment Agency said that while the more severe impacts from the storm are likely to be wind-related, minor flooding is likely in parts of the North East and the West Midlands over the weekend.

Katharine Smith, flood duty manager at the EA, said: “Environment Agency teams are out on the ground and will support local authorities in responding to surface water flooding.

“We urge people not to drive though flood water – it is often deeper than it looks and just 30cm of flowing water is enough to float your car – and people should also take extreme care on coastal paths and promenades, and avoid them where possible in the South West.”