a single block is a whole biome 

an ice block that genrated near a beach

as you can see in the screenshot looks like snow particles was only on 1 block

and the rest was rain

not only that block was effected 

there was other 3 block act the same

if you look at the screen shots you will see that the biome changes from frozen ocean and cold ocean 

even tho it's only 1 block 

(if i forget to write some notes tell me)

note: 

• the game is not modded i use optifine and it does't effect the world genrating
• i place the stone block just to show the biome switching from frozen to cold ocean
• the seed is in the screen shots