Severe weather warnings are in place in Northern Ireland, Scotland, Wales and western counties of England, with snow and sleet closing roads in Scotland.
Drifting snow
In Scotland, gale force winds and driving rain are battering large parts of the country.
Travelling conditions have been poor and some ferries have been disrupted.
Speed restrictions were in place on many bridges and fallen trees caused problems on the A82 near Drumnadrochit.
There is also snow on the higher roads such as the A9 at Drumochter in the Highlands and on the M74 north of Moffat in Dumfries and Galloway.
Grampian Police said the A93 Glenshee to Braemar road was closed due to drifting snow and high winds and would remain closed for some time.
But snow triggered optimism in Scotland's ski resorts as flakes began to fall at Lecht ski resort in Aberdeenshire and Cairngorm Mountain ski resort near Aviemore.
Cairngorm operations manager Colin Matthew said: "We started skiing at the end of November last year, so we hope it's the start of a good year."
In Northern Ireland, motorists were advised to drive with extreme caution after reports of ice, flooding, debris and fallen trees on the roads after overnight storms.
A number of severe weather warnings have been issued by The Met Office.
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