Four people have been killed on Scotland's roads as freezing conditions continue to grip the country.
A man died and one other man was hurt in a three-lorry crash on the A9 near Dunkeld, Perthshire, at about 0520 GMT.
In Ayrshire a man was knocked down and killed while walking along the A78 near West Kilbride just before 0100 GMT.
And at about 1610 GMT a male driver and his female passenger died in a two-car collision near the Highland village of Croy.
Although the majority of Scotland's roads are passable, Grampian Police have warned drivers to take care following overnight snow.
Officers said already frozen surfaces with fresh snow had created very slippery conditions.
Heavy snow is expected to fall in Aberdeen, Aberdeenshire, the Highlands and Orkney later on Thursday and into Friday with the Met Office saying that there could be up to 10cm in some areas.
Tayside Police said it was not yet known if the A9 crash was caused because of the icy road conditions.
It is understood that two HGVs collided head on, and a third ran into the back of them.
The police said that the man who died was aged 57 and the seriously injured man is 23.
A police statement said: "The A9 has been closed to northbound traffic at Inveralmond roundabout, Perth with only cars and other light vehicles being diverted to the A85 to Gilmerton, then the A822 and A826 to Aberfeldy before returning to the A9 at Balinluig.
"Southbound cars and light vehicles are being diverted via the A924 at Pitlochry to Blairgowrie thereafter the A93 to Perth.
"There are no diversions in place for heavy vehicles and a southbound diversion is still to be confirmed."
Strathclyde Police said the pedestrian who was struck by a vehicle in Ayrshire died at the scene. The name of the dead man has not been released.
The whole of Scotland experienced another night of sub-zero temperatures with -15C being recorded at Strathallan in Perthshire.
The country's councils and the trunk roads agency Bear Scotland have been out gritting and ploughing major routes.
At airports, flights are starting to get back to normal, but there continue to be delays and cancellations at Aberdeen Airport.
Meanwhile, the Scottish government said it could lay on a fleet of buses to help stranded travellers make their way north of the border for Christmas.
Transport Minister Keith Brown said if there was enough demand, coaches would be hired to assist people in getting to their destination.
He has spoken to bosses at British Airways and UK Transport Secretary Philip Hammond to see if the problems in England were easing.
A message was also put out via Twitter to assess what demand there was from stranded travellers.
The results of that will be know later and Mr Brown said coaches could be laid on "if that proves to be necessary".
He told BBC Radio Scotland's Good Morning Scotland programme: "All we are saying is if there is going to be a big backlog due to the problems at Heathrow and so on we have done a number of things to make sure we can lay on extra buses if that proves to be necessary.
"So far it is not, but it is better to be prepared than to be caught cold."
Mr Brown said there was now "some clearing of the backlog that there was for Scottish travellers coming back through the London airports".
He added: "There were problems yesterday but British Airways are confident they're getting through the backlog of air flights to Scotland."
"We want to make sure everyone that wants to get back to Scotland, or indeed people that want to leave Scotland for a break over the Christmas period, are able to do that."