When you put an anvil one block above snow (not on the snow, block above it means that the anvil needs to fall) it will stay on the air. If you put the anvil two blocks above the snow it will fall and break the snow.
Related issues
Attachments
Comments
migrated
[media][media][media]
Duplicate of MC-838.
its not the same thing, this guy is talking about gravel on torches
A gravitiy affected block will only fall if there is an air block beneath it.