you are likely to find Snow in/at/on Ground. you are likely to find Snow in/at/on North. North is related to Main. 
Contrast is a type of Comparison. Comparison is related to Equal. Equal is related to Equivalent. Counterpart is a type of Equivalent. 
Ground <--AtLocation-- Snow --AtLocation--> North <--RelatedTo--> Main 
Contrast --IsA--> Comparison <--RelatedTo--> Equal <--RelatedTo--> Equivalent <--IsA-- Counterpart 