A new limited time mode, Ice Storm, will likely be available after the live Fortnite Ice Storm Event.
The Ice sphere, or the orb, was placed inside the Fortnite map above Polar Peak since the v7.20 update.
The ice sphere contains the Ice King, a skin which is available in the game as part of the Battle Pass, which will likely be released during the live event. The live event will take place at 7pm GMT and some players noticed their game mode playlist updated ahead of time, teasing a brand new LTM coming to the game.
The Ice Storm LTM will likely be coming directly after the event takes place and will be available in Solo, Duos and Squads. The LTM will likely feature the winter zombies, a reskin of the cube monsters that were available in the Fortnitemares event and the team terror LTM.