Blizzard

A whirling vortex of ice expands in a 240-foot-radius, 480-foot high cylinder at point you can see; this area counts as difficult terrain for any creature attempting to fly through it. Creatures in the cylinder when it appears must make a Constitution saving throw or suffer 6d8 cold damage and have their movement speed reduced by 10 feet; creatures that succeed on the save suffer half damage and are not slowed. 

Creatures that end their turn in the cylinder must make this saving throw as well, suffering the same effects. If this spell decreases a creature's movement speed to 0, they are incapacitated as they are coated in a layer of ice. Creatures that are reduced to 0 hit points by this spell are frozen solid until they thaw (which takes 1 hour) or until they take fire damage.

Fire damage in the area of the cylinder is halved, and any concentration checks made to maintain spells are done at disadvantage.