I'm building an extremely long elevated boatway and am trying to figure out what blocks I could use to hold in the water/guide the boat without needing to light them. My boatway, however, passes through quite a few snow biomes. I know that snow won't collect on glass, but since glass is labor intensive I was hoping to use cobble slabs. Can snow accumulate on slabs or any other transparent blocks? If so, will they then be able to spawn mobs?