I found these photos at 2pie.blogspot.com.
Apparently they are quite simply faces pressed in powder snow resting on cars.
The beauty of these rests not only in their formal aesthetic properties, but their momentary impermanent existence and the experiential element of their creation.
These works are also evidence of the merits of the internet and global communication. Without it the works would have only existed for their creators on the street in a city, for a moment.