Heavy snow and hail showers are affecting the Western Isles.
The Arctic blast is accompanied by strong winds with a force eight gale forecast for South Uist and Barra overnight.
The Met Office issued a yellow alert for the icy conditions which are due to continue over the week.
The Met Office said snow showers will continue through Tuesday and Tuesday night, although perhaps more of sleet and hail near some coasts.
Showers will be accompanied by hail and lightning at times which could cause disruption to power supplies from lightning strikes.
Services such as mobile phone coverage may be affected.
Strong winds bring the potential for temporary blizzard conditions and drifting of lying snow, mainly over high ground.
Motorists are urged to drive to the conditions and be prepared.
Travel delays on roads are possible, as are public transport cancellations.
Some roads and pavements will turn icy, increasing the chances of accidents or injuries.
Snow alert for Western Isles
16 January 2018