Cascade of Frost

A whirling blizzard forms around you, imbued with the arctic winds of the Plane of Ice. For the duration of the spell within 60 ft. centered on the caster, a freezing whirlwind forms, heavily obscuring all objects and creatures within its radius. Objects less than 15 lbs. that are not fastened down or being worn or carried are hurled around in the whirlwind. All creatures, except for the caster, who start their turn in the whirlwind must make a Constitution Saving Throw against your Spell Save DC, taking 4d8 cold damage and 1 level of exhaustion, or half as much and no exhaustion on a success. The wind blows at 25 mph, making all ranged weapon attacks within the radius occur at disadvantage. Every foot of movement within the radius costs 2 movement speed. As an action on each one of your turns, you may magically hurl a concentrated blast of roiling frost, which extends out in a 5 foot wide, 90 foot long line. Each creature caught in the blast must make a Constitution Saving throw against your Spell Save DC, taking 6d8 cold damage and having their movement speed halved on a failure, or taking half as much with no movement speed reduction on a success. Creatures reduced to 0 hit points by any cold damage caused by this spell are frozen solid, as though by petrification. 

At Higher Levels:
When you cast this spell using a 9th level spell slot, the cold damage for both the whirlwind and the arctic blast's damage increase by 2d8. Furthermore, the area within the next 5 miles of the spells casting exists under the effects of extreme cold  temperatures, and is lightly obscured by heavy snow and sleet. The extreme cold persists for 10 days, and the snow persists for 30 days. During this time, travel speed is halved.