THEY call it thundersnow or a snow bomb and yesterday Scotland found out all about this weather phenomenon.

Thunder and lightning accompanied heavy snowfalls and blizzards in the Glasgow and Lanarkshire areas, while the country as a whole saw massive transport problems and other disruption including mobile phone difficulties, all due to ice and snow.

Police Scotland have issued a strong warning of continuing havoc today after the Met Office upgraded its yellow warning of snow to amber and extended the area affected into the central belt as well as the south-west and parts of the Borders with more snow expected overnight and this morning.

There were also predictions of severe gales heading Scotland’s way later in the week.

Transport Minister Humza Yousaf said: “The Met Office has upgraded its snow warning for parts of south west and central Scotland, with the areas affected by the amber warning set to see heavier snowfalls and greater disruption to transport.

“The snow and ice is likely to lead to difficult driving conditions, so I’d urge all travellers to take extra time and plan their journeys in advance. The high winds forecast for later in the week may also see some bridge restrictions.”

A spate of accidents took place on Scotland’s roads though there were no reports of fatalities. A Stagecoach bus between Edinburgh and Dumfries skidded off the A702 near Biggar with its front landing in a field, while in Dumbarton a car flipped onto its roof on the A82 — again there were no injuries in either accident.

Ferry services were cancelled and air travel was hit — Inverness airport was closed for most of the morning while there was disruption to flights at Aberdeen and Glasgow, the latter briefly closed to allow clearing operations.

Across the country more than 100 schools and nurseries were closed with 10,000 pupils affected, and in North Lanarkshire, all prelim exams for secondary pupils were postponed.

The police warning yesterday afternoon was comprehensive: “Police Scotland is advising drivers that conditions for travel are extremely poor and there is a high risk of disruption for road journeys in Dumfries and Galloway, the western part of the Scottish Borders, West Lothian, Falkirk, North Lanarkshire, South Lanarkshire, Glasgow, East Renfrewshire, East Ayrshire and South Ayrshire areas. If you do travel, you are likely to experience significant delays.

“Congestion caused by vehicles may restrict emergency, recovery or winter maintenance vehicles from providing essential assistance or from clearing roads.

“Drivers of HGVs should drive with extreme caution and be aware that you may be requested to park at a suitable position by the police.”

Head of Road Policing, Chief Superintendent Stewart Carle, said: “Winter driving is a question of common sense and 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 considering postponing your journey or 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. Charge your mobile phone and plan your route as well as alternative routes. Listen to media broadcasts, especially local radio, and visit the Traffic Scotland website.

“For all other areas with the exception of Aberdeen City and some neighbouring parts of Aberdeenshire/Angus Police Scotland is advising people that conditions for road travel are hazardous and drivers should exercise extra caution.

Weather forecasts are constantly being monitored at Traffic Scotland and will be updated as and when things change.”

The Met Office confirmed the presence of thundersnow in the central belt: “If the weather is cold the rain associated with a thunderstorm can then fall as snow and thus is called thundersnow.

“This is unusual because it can only occur in a few months of the year.”