Christmas shoppers have been told to take extra care on Saturday, with widespread heavy freezing rain expected to create hazardous conditions on the UK’s roads.

The Met Office has stepped up weather warnings with snow and freezing rain due across large parts of the UK this weekend, prompting fears of travel delays and power cuts. The Met Office is urging people to take extra care when travelling on one of the busiest weekends in the lead-up to Christmas.

Storm Deirdre has prompted six yellow and amber weather warnings that cover almost the entire UK apart from London and the south-east, where heavy rain is still expected.

The Eden Project in Cornwall was forced to close its doors on Saturday because of flooding. The tourist attraction apologised on Twitter, and said it was offering refunds or exchanges to people who had booked tickets in advance.

A new amber alert issued on Saturday warned of freezing rain and a prolonged period of heavy snow developing in the Scottish Borders in the afternoon. Another predicted potential blizzard conditions bringing disruption to transport and infrastructure in central and northern Scotland between Saturday and Sunday mornings. A third was issued for widespread freezing rain from the southern Pennines to central Scotland.

Freezing rain is rare in the UK and can be dangerous because of the rapid formation of black ice, which can be difficult to see and very slippery. It can lead to road accidents and render pavements and cycle paths impassable.

“We are going to see widespread freezing rain events, which is fairly unusual,” said the Met Office forecaster Mark Wilson, adding that the north of England and southern Scotland would be worst hit.

“The concern is there will be lot of people on the roads at this time of year, and black ice can produce very dangerous driving conditions, so our strong recommendation is to be mindful of the very difficult situation on the roads,” he said.

Police Scotland said people should only travel if they consider it necessary.

A statement read: “Winter driving is a question of common sense and all drivers should ask themselves if they really need to travel when conditions are poor. No one should ever place themselves at risk on the road and it may be worth making alternative arrangements such as delaying travel until conditions improve, or using public transport.

“If you are travelling on the roads you should ensure you and your vehicle are adequately prepared for the conditions, making sure you have sufficient fuel and supplies such as warm clothing, food and water in the event you are delayed for several hours.”

The Scottish transport secretary, Michael Matheson, said delays and cancellations on public transport were possible. “I would encourage people in the affected areas to consider whether they need to make their journey. If they do, they should expect disruption,” he said. “Drivers should plan their routes, leave plenty of time, follow Police Scotland travel advice and drive to the conditions.”

Yellow warnings for wind, rain, sleet and ice were in place for swathes of the country on Saturday, one of the busiest shopping days of the year. The Met Office said the amber warning for freezing rain covered central Scotland, Tayside and Fife, the Lothian Borders, Strathclyde, the East Midlands, the north-east, the north-west, West Midlands, Yorkshire and Humber. A yellow warning for rain and wind was in place across Northern Ireland, south-west England and parts of south Wales.

The worst of the weather should be over by Sunday, Wilson said. “Sunday, thankfully, is a much better day, and while it will be a frosty, icy start, most areas will be calmer and brighter, with higher temperatures and a decreased risk of ice,” he said. “Our recommendation is for people to do their Christmas shopping on Sunday and stay in and watch Christmas films on Saturday.”