After a snowfall (rain) snow piles up into complete blocks and even higher in snowy biomes. You can also see a clear demarcation line between chunks of snow biomes where there is no snow accumulation and the chunk where the player is.

Steps to Reproduce:
1. Go to snowy biome (tundra, taiga etc)
2. Wait for snowfall (rain)
3. Allow snow to pile 

Observed Results:
Snow piles up until it gets to be a full snow block and sometimes even higher than 1 block

Expected Results:
Snow should not pile up so high and should melt a little in the day as to prevent full snow blocks from forming.