Blue Snow deck focused on Snow triggers, locking down your opponents' creatures, and then overwhelming your opponent with large creatures you cast real cheap.
Ascendant Spirit comes out cheap and can grow more formidable if you desire, but hits the Snow permanent trigger for 1 mana. Icehide Golem also costs 1 mana and provides a 2/2 creature, so not bad there.
Frost Augur has a cheap CMC and lets you draw one of your Snow cards (80% of the deck) for 1 mana.
Iceberg Cancrix lets you Mill your opponent for each Snow permanent you play.
For heavy hitters, your 100% Snow mana base means you can play Iceberg Kraken for 6 or less starting on turn 6 that gives you an 8/8 on the field with the added benefit of locking down your opponents' creatures and artifacts for a turn. Marit Lage's Slumber lets you Scry regularly and, given the overall low CMC curve, will net you a 20/20 Flying and Indestructible creature by turn 5 the latest.
Lastly, Mana Leak and Counterspell halt your opponents' plans while Winter's Rest permanently locks down your opponents' creatures and a full playset of Chart a Course lets you take advantage of the overall low CMCs by giving access to cards to play to hit the Snowfall triggers built in the deck.
