Figure out this riddle....... ?

[NatLie]

what is blue overhead and hates to be walked on when it snows...?
my sister is trying to figure. what a loser of her not to now!! its 4th riddle. : )
lol
omg. thats what my sister said. and its not the GRASS.. (did i just make a riddle too hard?)
i mean is not the SKY.

 

[joanie]

The sky?
Rain?
I'm going with rain.

 

[tankt2020t]

dirt

 

[Don]

i'll answer just to say this.
it is OBVIOUSLY not the SKY.
who can walk on the sky???????????????????

 

[shanon]

....a frozen lake?

 

[Alex]

yep its the sky