Take the Going-To-The-Sun Road in Glacier National park. around mile marker 12 there is a turn out in which you can walk down by the water. In winter, take snow shoes. It's deep.
Be prepared for quick changing weather. During the winter time, always take a pair of snow shoes because some places you have to trek into for great shots.
Winter in Glacier National Park has always been one of mu favorite times of the year because of the solitude, the snow on the mountains and the changes in weather. This day was a beautifully calm day and Lake McDonald was like glass.