The water in the seems to shimmer and vibrate, and the temperature begins to drop, as you prepare to unleash a local torrential blizzard upon your foes.

Round 1. When you cast this spell, the water vapour in the air coalesces into multitudes of small spheres of water, each exploding in a gush of water, causing the area to be coated in a dense mist. All creatures within range must make a DEX saving throw. On a failed save, they take 12d8 WATER damage, and half damage on a successful save.

All flames are extinguished, and the area becomes Lightly Obscured. Any FIRE damage dealt to creatures or objects within this area are reduced by half for the duration of the spell.

Round 2. On your next turn, the mist gets thicker because the temperature drops dangerously low, causing the area to become Heavily Obscured. Also, the ground becomes slick with ice, making it Difficult Terrain. All creatures within the area, or any creature who enters the area for the first time on their turn, must make a CON saving throw. On a failed save, they take 12d8 ICE damage and they receive 3 levels of

Brittle

Round 3. On the subsequent turn, the wind picks up and shards of ice begin to form in the air, turning into large blocks of hail, which get tossed around by the howling wind. All creatures within range must make a DEX saving throw. On a failed save, they take 15d12 ICE damage, and half damage on a successful save.

A creature brought to 0 HP by this spell on Rounds 2 or 3 becomes encased in a thick layer of ice until it thaws. The ice is 30cm thick, magickal, and is impervious to spells below 9th level (excluding spells such as Dispel and Anti-magick Field, or similar), has 30 HP, has an AC of 25, and a damage threshhold of 20.

After Round 3, the mist is dispersed and the area is no longer Heavily Obscured. However, all areas affected by the blizzard remain Difficult Terrain for 1d4 days due to massive amounts of snow on the ground.