Blizzard soul

Blizzard soul sorcerers harness the coldest magics possible in a chilling balance of offensive and defensive capabilities. Manipulating the temperature of the surrounding area and nearby creatures to sway the flow of battle. 

Cold blooded

You gain resistance to cold damage.

Glacial Protection

You can use your reaction to crystalise the skin on your body with ice. If you are wearing light or no armour, you can use your reaction to raise your AC equal to your Constitution modifier (minimum of 1) until the beginning of your next turn. You can do this a number of times equal to your proficiency bonus. Regain all uses after a long rest.

Lingering chill

At 6th level you have learned how to chill even the toughest of foes right down to their core. When you deal cold damage with a spell of 1st level or higher, you can spend 2 sorcery point per damaged creature to attempt to freeze the creatures. The creatures must succeed a constitution saving throw or be petrified. At the end of each of their turns or whenever the creatures sustain damage, they may make a constitution saving throw against your sorcerer spell save DC. If they succeed the saving throw, the effect ends.

Winter's stride

At 14th level, as a bonus action, you can teleport up to 90ft in any direction to a location you can see. Anything you pass through must make constitution saving throw, inanimate objects automatically fail. If they fail the save they take 4d10 cold damage, or half as much on a success. In addition, any ground or liquid you pass over or through freezes. You can use this ability once per long rest.

Permafrost

At 18th level you fully master your inner blizzard. As an action, you may spend 5 sorcery points to emit a blizzard aura in a 50ft Sphere centred on your location for 1 minute. You may choose any number of targets inside the aura to take 4d10 cold damage at the start of their turns. While the aura is active, you have advantage on all attack rolls made with cold damage. Creatures of your choice within the aura have disadvantage on saving throws against cold damage spells and Lingering Chill.