The Met Office issued amber and yellow warning covering most of Scotland overnight saying there will be blizzard conditions and westerly gales. In some areas up to eight inches of snow are expected.
The public were warned to prepare for travel disruption.
Researchers recording waves off the north-west coast of Lewis said average peaks measured between 42ft-45ft during the day.
It comes as high winds and snow started to hit Scotland with conditions in the mountains described as "atrocious".
Scottish Transport Minister Keith Brown said: "Looking at the latest forecast for frequent and at times heavy snow combined with gales force winds will mean a testing journey for many this evening and, crucially, in rush-hour tomorrow."
Several schools in the Western Isles were closed yesterday and about 200 homes were without power and ferry sailings across Scotland were disrupted.
The gusts forced the closure of the Forth Road Bridge, the Erskine Bridge, Clackmannanshire Bridge and Skye Bridge to high vehicles.