That is not a metaphor. "The snow was a dirty blanket over the parking lot" would be a metaphor. It is a figure of speech that compares two very different things- snow and a blanket.
as soft as a blanket
That is a simile because it is comparing the warmth of the breeze to the warmth of a blanket using the word "as."
You are going to be hard-pressed to find a metaphor for blanket since metaphors use a common object to symbolize a more complex concept. Blankets are fairly common objects so they usually become the symbol. You will find snow, metaphorically blanketing the ground and you will find a 'wet blanket' in attendance at most parties. You will find 'blanket rules' that have nothing to do with a bed and if you look hard enough, you will find a 'security blanket' that may not be made of cloth.
It means that the street is completely covered by a solid sheet (or metaphorical blanket) or snow. Someone looking at it would only see snow, and not the street.
A metaphor for fog could be a "veil of mystery" or a "blanket of uncertainty" that obscures clarity and vision.
the snow howled
I think its a metaphor. its not using like or as, like all similes are supposed to.
A snow blanket
"Blanket of softness beneath your feet."
The snow blanket does not affect the planting or harvesting of cropes in farmville, so yes you can plant crops.
rain