From VG247: “Over the weekend, the Ice Storm in-game event began in Fortnite, bringing with it some new challenges.
The Ice King unleashed an icy storm on the map, which is now covered in snow. New challenges unlock every day and if you complete all 13 challenges youll be rewarded with the Winters Thorn Glider. As an incentive, youll also receive the Blue Metallic Wrap once youve completed six of the Ice Storm challenges.”
Source: N4G PC Fortnite Ice Storm challenges – how to destroy Ice Fiends and damage Ice Legion