Night Snow at Kambara - 1833
This woodblock and it's companion to the right both show that the artist is not the only determinant of the artistic quality. The woodblock printer used different techniques to create effects.
In "Night Snow at Kambara," gradients were created by wiping the ink off gradually, so that the print has the black-white gradients which imply snow and shadow.
This print is nearly monochrome, sparingly using color only to hilight the people moving through the gray, somber scene.
Drum Bridge and Sunset Hill, Meguro - 1857
In "Drum Bridge and Sunset Hill" the snow effect is created by not applying color where the snow should be.
These "blank" areas were then filled in with tree branches, grasses, etc. This later technique created a lighter, fluffier snow.
This technique is not used exclusively -- there are gradients of snow