Commuters are facing major delays on the roads and railways this morning as Storm Chandra strikes Britain.
The M48 Severn Bridge was closed this morning, with the Humber Bridge also shut to high-sided vehicles due to wind.
Snow was also forecast in parts of the country as a number of weather warnings came into force in the early hours of the morning.
Over 300 flood alerts have been issued for England, Wales and Scotland, including one severe warning for the land at River Otter near Sidmouth.
Almost 250 schools have been closed across Northern Ireland "due to severe weather", local authorities have said.
Dozens of schools have also been closed across England and Wales.
National Rail issued a warning that "poor weather may affect South Western Railway services until the end of the day", while traffic between England and Wales was being diverted over the M4 Prince of Wales Bridge.
Gwent Police said that the A40 was flooded between Abergavenny and Raglan, while sections of several roads in Dorset, Somerset and east Devon were closed due to flooding.
Forecasters had warned that flooding and travel disruption were likely with significant snow across higher ground in some northern parts of England and Scotland.
Several weather warnings were in force on Tuesday, including amber warnings for south-west England and the eastern coast of Northern Ireland for rain and wind.
National Highways said the A66 is closed between the A67 near Bowes in County Durham and the A685 near Brough in Cumbria because of snow. Drivers travelling across the Pennines have also been advised to "plan ahead and consider alternate routes."
The River Ouse has burst its banks
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Storm Chandra is striking Britain this morning
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Flood alerts in place across England
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Met Office chief forecaster Paul Gundersen said: "Initially, strong winds will impact the Isles of Scilly, western Cornwall and south-west Wales which are still vulnerable after Storm Goretti, gusts of 70 to 80mph are possible here.
"Heavy rain is an additional hazard as it falls on saturated ground in Dorset and southern parts of Devon, Somerset and Cornwall.
"As Chandra interacts with colder air further north snow becomes a hazard, with 10-20cm of snow possibly accumulating over higher ground in the Pennines, southern Scotland and the Highlands.
"With a complex spell of weather, its important people stay up to date with the forecast and any warnings in your area."
Flooding in York where the River Ouse has burst its banks
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LATEST DEVELOPMENTS
The A303 is closed between the A30 at Upottery in Devon and the A358 at Horton Cross, Somerset. In Dorset, the A35 is closed in both directions between the A352 Max Gate junction and the B3150 Stinsford roundabout near Dorchester.
Rail lines are being disrupted across the South West, including between Par and Newquay in Cornwall, between Castle Cary and Taunton in Somerset, between Salisbury in Wiltshire and both Southampton Central and Romsey in Hampshire and between Exeter St Davids and both Okehampton and Barnstaple in Devon.
Meanwhile, Transport for Wales said a tree is blocking the railway at Llanbister Road station near Llangunllo in Powys, meaning there are no services between Swansea and Shrewsbury.
RNLI Water Safety Manager Joel Ninnes said: "Sadly, the south west has been hit by a succession of storms already this month, and we are bracing ourselves for the impact of Storm Chandra.
"With the ground already sodden, cliff edges are unstable and coastal structures already undermined by recent strong winds and rough seas. Our advice is to keep well away from cliff edges and sea fronts."
Much of Northern Ireland has been struck with flooding in recent weeks
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Storm Chandra is the next storm to be named by the western Europe storm naming group list shared between the UK, Ireland and Netherlands.
RAC mobile servicing and repairs team leader Nick Mullender said: "Flooding is highly likely, making many roads dangerous. Our message to drivers is simple: do not drive through standing water unless you are completely certain the water is shallow enough and it’s safe to do so.
"In these conditions, drivers need to slow down and stay alert. Wet roads can double stopping distances, so taking a cautious, steady approach and allowing extra time to react is essential.
"If your vehicle already has known faults, now is not the time to take risks. Avoid unnecessary journeys and get issues fixed promptly by a trusted mobile mechanic or local garage."