Large parts of the UK were blanketed with snow as the country got its “first taste of winter”, which brought school closures, train delays, difficult driving conditions and an appeal to check in on vulnerable people.

Met Office yellow severe weather alerts for snow and ice were in place across northern Scotland, the Midlands, northern England, north Wales and Northern Ireland.

Snow also fell in areas not covered by the alerts, including central London.

The cause is an Arctic maritime air mass, meteorologists said, which means that while the snow is expected to clear, it will be extremely cold all week.

In mid- and north-east Wales, more than 130 schools in Wrexham, Powys, Denbighshire and Flintshire were closed because of the snow. In Kirklees, West Yorkshire, five schools were closed.

There were delays and cancellations across the rail network with Northern Rail, which operates across northern England, urging passengers to check before they travelled as services were disrupted.

Affected areas included the Bradford Interchange and Huddersfield line, and also between Halifax and Hebden Bridge and Hull.

East Midlands Railway said there was disruption on multiple routes, including the cancellation of trains between Nottingham and Mansfield.

South Western Railways was running trains at a reduced speed on all lines on Tuesday because of conditions.

Merseyrail said the first service on each line in north-west England would run without passengers so that the tracks could be checked for snow and ice.

Local authority gritters were out across the UK but a number of roads were deemed impassable and closed on Tuesday morning because of the conditions. They included the A44 in Powys, the A628 between Sheffield and Manchester and the A57 Snake Pass in Derbyshire.

Darren Clark, the severe weather resilience manager for National Highways, urged drivers to keep their distance and reduce their speed.

“Even in conditions that seem normal, and where the snow is not settling, it can be slippery if ice patches have formed, or where fresh grit has not been worked into the carriageway,” he said.

“Drivers should plan their journeys, monitor weather reports and pack a snow kit of blankets, food, water and a shovel.”

Scotland recorded its coldest early winter temperatures since 1998 with a reading of -11.2C recorded in Braemar, Aberdeenshire.

The Met Office had warned people that the “first taste of winter” was on its way, advising people to get their woolly jumpers ready.

The warning came after the UK Health Security Agency (UKHSA) issued the first amber cold weather health alert of the season this week.

The amber warning covers the east and north of England, the Midlands, and Yorkshire and the Humber, with yellow alerts coming into place for the south-east, south-west and London at 8am on Tuesday, lasting until 6pm on Saturday.

The charity Age UK warned that the conditions could be dangerous for vulnerable people, including elderly people.

Dr Agostinho Sousa, from the UKHSA, said: “This is the first amber cold weather health alert of the season, but we can expect more as we approach winter, and it is vital to check in on vulnerable friends, family and neighbours to ensure they are well prepared for the onset of cold weather. Particularly if they are elderly or otherwise at increased risk.”

The Age UK director, Caroline Abrahams, said the charity was worried that the loss of the winter fuel payment had caused many older people to be “extra fearful” about turning on their heating this winter.

“With high energy bills and food prices it is understandable that some may think they have to cut back on food and turn their heating off, but prolonged exposure to cold temperatures can have a serious impact on an older person’s health, especially if they are already trying to manage existing illnesses,” she said.

Abrahams said it was “vital” that older people stayed “fit, warm and well if they can” by having hot food and drinks throughout the day, wrapping up warm and sleeping with the windows closed.