Heavy snow storms which have closed roads and schools in the north began to spread across Scotland on Friday.
The snow is expected to continue at the weekend
Diggers and snowploughs were out in force to keep many main routes open, but police said some stretches were still extremely treacherous.
Hundreds of schools across the country, including in the north east, Highlands and Shetland, have been closed for a fourth day.
Forecasters say the weekend was likely to bring more snow.
Snow has now also affected parts of Dundee, Fife, Kintyre, Dumfries and Galloway, Glasgow and Edinburgh.
Almost 250 primaries, secondaries and nurseries in the north east alone cancelled lessons.
Snow is spreading across more of the country
All the schools in Shetland were closed, and many schools also shut in the Highlands, Angus and Stranraer.
It left around 100,000 pupils off school across the country.
Many roads in the Highlands have been affected by drifting snow, with the situation deteriorating, and conditions were bad on routes through Fife, Tayside and Angus.
Inverness Airport was closed, and flights in and out of Aberdeen were disrupted.
There was disruption on rail services in Aberdeen - which also experienced thunder and lightning.
Grampian Police urged motorists to be extra cautious and only travel if the journey was essential.
Jurors at the High Court in Edinburgh were sent home because of bad road conditions in the capital.
Forecasters say snow and sleet could continue through until Monday.
Roads have again been badly affected
The Scottish Premier League (SPL) has ruled that the game between Celtic and Aberdeen in Glasgow on Saturday will go ahead - despite Aberdeen's plea for a postponement due to road conditions.
Aberdeen head of operations Duncan Fraser said: "The weather is the severest we have experienced for many years.
"With the authorities urging people not to travel, asking for a postponement is the only sensible option open to us."
However, an SPL spokesman said: "The match will go ahead as planned."
Meanwhile, ice on the River Dee has forced Saturday's annual Aberdeen Universities Boat Race to be postponed.
The Stranraer half marathon and the match between the town's football team and Ross County have also been cancelled.