Storm Sorcery (Snowstorm)

Your innate magic comes from the power of elemental ice. Perhaps you endured the harshness of a great blizzard or avalanche in a frozen landscape, or returned from a journey through a glacial pass with newfound power. Maybe you lived amongst the great forces of nature moulded of elemental ice, such as a frost giant's fiefdom or white dragon's hunting grounds. Whatever the case, the magic of the blizzard permeates your being.

Snowstorm sorcerers are invaluable members of an expedition into the frigid deserts and ice peaks at the ends of the world. Their magic allows them to exert control over ice, snow and weather in their immediate area.

Ice Speaker

The arcane magic you command is infused with elemental ice. You can speak, read, and write Primordial. Knowing this language allows you to understand and be understood by those who speak its dialects: Aquan, Auran, Ignan, and Terran. Additionally, any creature native to the Arctic or Mountain environments can understand what you say or write in Primordial, regardless of languages.

Boreal Magic

Starting at 1st level, you can use a bonus action on your turn to cause a freezing cloud of ice to briefly surround you, immediately before or after you cast a spell of 1st level or higher. Doing so causes any creature within 10ft of you to have their movement speed halved, and require them to make a Constitution saving throw against your sorcerer spell save DC or suffer disadvantage on their next attack roll or ability check.

Heart of the Blizzard

At 6th level, you gain resistance to cold damage. In addition, whenever you start casting a spell of 1st level or higher that deals cold damage, mistral magic erupts from you. This eruption causes creatures of your choice that you can see within 10 feet of you to take cold damage  equal to your sorcerer level.

Arctic Guide

At 6th level, you gain the ability to subtly control the weather around you.

If it is hailing, you can use an action to cause the hail to stop or start falling in a 20-foot-radius sphere centered on you. Hail under your control as an environmental effect deals 1d6 cold damage to each creature at the start of their turn. You can end this effect as a bonus action.

If it is snowy, you can use a bonus action each round to direct the snow into falling to form a 5ft by 20ft line perpendicular to you at a range of 50ft, with a height of 5ft. This snow wall is compact enough to block line of sight, provide half cover and serve as difficult terrain for creatures of your choice. However, once a creature passes through or attacks a section of the wall, it dissipates in a flurry of powder snow.

Tundra’s Fury

Starting at 14th level, when you are hit by a melee attack, you can use your reaction to deal cold damage to the attacker. The damage equals your sorcerer level. The attacker must also make a Strength saving throw against your sorcerer spell save DC. On a failed save, the attacker is restrained by ice for one minute, or until another creature spends an action to break the ice.

Mistral Soul

At 18th level, you gain immunity to cold damage.

You also gain a magical flying speed of 40 feet and can pass through solid ice unimpeded until the end of your turn. You take no damage from ending your turn encased in ice in this way. As an action, you can halve your movement speed for 1 hour and choose a number of creatures within 30 feet of you equal to 3 + your Charisma modifier. The chosen creatures gain the same abilities at your reduced movement speed for 1 hour. Once you halve your movement speed in this way, you can’t do so again until you finish a short or long rest.