Scotland struggles in big freeze
Severe winter weather in Scotland has continued to cause disruption across much of the country.
About 850 schools were closed from Shetland to the Borders.
Driving conditions are hazardous and there are roads closures in Perthshire, the north east and Highlands. Edinburgh Airport was closed at 1800 GMT and there is also disruption to trains.
About 3,000 homes lost electricity, many in Tayside and Central. Extra staff were called in to fix the fault.
Power supplier Scottish Hydro said it hoped to have all its customers reconnected by the end of the day.
By 2200 GMT about 450 homes in the region were still without electricity after widespread problems with "line icing".
A Scottish Hydro spokeswoman said engineers were still hopeful of getting everyone reconnected but may not be able to reach customers in the more inaccessible areas.
Scottish Power had no major problems but extra engineers were put on standby.
Roads, including the A9 between Perth and Dunblane, the M90 near Perth, the A939 Ballater to Corgarff Road and the A940 between Forres and Grantown were all closed.
The A9 northbound from Dunblane was reopened at about 2140 GMT and was "passable with care".
But it remained closed southbound between Broxden roundabout in Perth and Keir roundabout at Dunblane.
A police spokeswoman said: "Drivers should completely avoid the A9 between Dunblane and Perth and should be aware that all side roads are equally affected and are unlikely to be passable.
"All major routes have been severely affected over the last 24 hours or so, with significant snowfall and drifting snow causing problems on the roads."
Further snow is forecast to fall throughout the night.
The Lecht Ski Centre in the Highlands was also closed on Monday.
Many motorists on the A9 had to abandon their vehicles on the road overnight.
An emergency rest centre, set up by Perth and Kinross Council after motorists became stranded, provided shelter to more than 600 people.
The centre was set up on Sunday at Perth's North Inch Community Campus when it became clear that people were becoming stranded on the M90, A90 and the A9.
About 60 people had arrived by 2000 GMT on Sunday.
By Monday morning, 669 had been registered.
Forecasters have warned that the cold snap will get worse this week, with temperatures plunging as low as -20C.
The coldest overnight temperature in the UK was Altnaharra in northern Scotland, which recorded a low of -16.1C.
The village saw the lowest temperature of last winter, with a reading of -22.3C in January 2010.
Air, as well as road travel, has been affected.
Edinburgh Airport was closed until 1400 GMT, when it reopened briefly, but then closed again at 1800 GMT.
Aberdeen Airport remains open but a spokesman warned of possible disruption.
A number of flights from Glasgow Airport were cancelled and others were delayed.
There was also major disruption on the railways, with the Glasgow Queen Street to Edinburgh service reduced to twice an hour and Glasgow Central to Edinburgh, via Shotts, reduced to an hourly service.
Various other services, including Ayr to Glasgow, were also been disrupted because of signalling problems.
However, ScotRail said 86% of its services had run on Monday.
A spokesman said: "We have maintained a resilient train service when alternative road options were extremely daunting."
He added that it was likely that contingency plans would remain in place on Tuesday. Customers should continue to check ScotRail's website before setting out and to allow more time for their journeys.
NHS Borders cancelled all outpatient appointments for the day and advised anyone with emergency issues to contact their GP or local medical practice.
A number of school areas were taking a St Andrew's Day holiday but hundreds of others were forced to close because of the conditions.
Celebrations in Edinburgh for the patron saint's day were cancelled.
Two of the marquees in St Andrew Square Garden were damaged by the snow and all events, including Tuesday's ceilidh, were called off for safety reasons.
Meanwhile, council workers in Midlothian were allowed to leave early due to the bad weather.
Prisoners clear snow
A Scottish government spokesman said: "Prisoners from Castle Huntly, Noranside, Shotts and Greenock Prisons are currently being used to clear snow locally.
"In addition we have reminded local authorities to use offenders on community service to help with winter emergency work."
A cargo of more than 26,000 tonnes of salt from Peru has arrived at the port of Leith.
This has come as one of the areas worst affected by heavy snow - Aberdeenshire - is having supplies of road salt rationed.
The authority said it had already used 12,000 tonnes of salt, compared to 3,500 tonnes at the same point last year. The council expects fresh supplies to arrive later this week.