Looking through walls with snow layers.

Step by step guide to the bug:

1. Place 8 snow layers on a scaffolding block
2. Jump in a boat
3. Row into the scaffolding block till your head is inside the snow layers

What I expected to happen:

To see the inside of the snow layers, as it is a 'transparent' block. 

Alternatively to see nothing and suffocate to death in survival, which would be the case for getting your head into a full block.

What did happen:

You can see through the snow layers and all connected blocks, you don't take suffocation damage. In a way this gives you the same sight as if you were in spectator mode.

Is this exploitable?

Yes, to some extend: You could potentially use this to make all the caves, mine-shafts, and dungeons visible in survival mode, if you make this setup at bedrock levels.