Does snow falling on a transparent block allow it to start spawning mobs?

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?

Snow can't fall on slabs, and therefore, won't spawn mobs (as stated in this question). Additionally, the Minecraft Wiki article for Snow states it can't fall on Ice or Glass. Therefore, they won't be able to spawn mobs either.