
Update: An in-game event, codenamed "Mooney", has been discovered by data-miners in the v7.20 files. This event includes the Ice Sphere spotted above Polar Peak.
The "Ice Storm" challenges have been leaked by @FortniteGameLAT, which include an "Ice Legion". It's possible we may be seeing an upcoming in-game Boss Battle at the end of the event!

This is backed up by leaks from data-miners which showcase a new part of the map, with fog, and an Ice King.
BP_MooneyLoader.uasset has some interesting stuff
— Lucas7yoshi_ // Fortnite News & Leaks (@lucas7yoshi_) January 15, 2019
"LoadMooneyMap"
"MooneyMap"
Stuff to override the time
References to Ice King and then an animation file
TV warning is connected to mooney event
Storm can be paused
BP_MooneyScripting.uexp has these text snippets
— Lucas7yoshi_ // Fortnite News & Leaks (@lucas7yoshi_) January 15, 2019
"Countdown"
"warning"
"No TOD Manager found- Starting loop to wait for spawn" (debug probably)
"Removing Fog
"Remove Fog Override"
"Adding Fog"
"HIDE ALL ICE KING VISUALS/AUDIO"
Animations for the event have been found, with the data-miner claiming that it might actually be tied to the previously leaked Marshmello x Fortnite collaboration!
all 5 mooney animations
— Lucas7yoshi_ // Fortnite News & Leaks (@lucas7yoshi_) January 15, 2019
Mooney is sphere related
Im starting to connect the mooney event to marshmello personally@HappyPower @bnwkr @Mxtive @TheCampingRush @FortniteINTEL @bodil40 @Merlalias pic.twitter.com/wAIL0ffc9U


Original article:
An event which involves an ice storm coming to the Fortnite map has been leaked in the in-game files by data-miners.
It could possibly be an in-game event that involves Polar Peak, in which a floating ice sphere has been spotted.

We'll have to see what happens in the event, but challenges have been spotted in the files (via @ShiinaBR).

Here are images giving warnings of the event (via SiloxLeaks):



Here are the sounds of the event (via HYPEX)
New event sounds! pic.twitter.com/h9bGY02IsA
— HYPEX (@HYPEX) January 15, 2019