Winterfest has become a New Years celebration, as today's challenge is to light frozen fireworks on the beaches of Sweaty Sands, Craggy Cliffs, or Dirty Docks in Fortnite. First of all, you need to visit the Winterfest chalet and open your vacation stocking. If it bugs a bit, complete any other challenges, then load it again, and it should work.
To light the frozen fireworks, you'll need to visit Sweaty Sands, Craggy Cliffs, or Dirty Docks beaches. You can find all the locations marked on the map above.
Moist sands
Look for the beach west of the pier.
Steep cliffs
Look for the beach near the mouth of the river.
Docks sales
Look for the beach north of Dirty Docks.
The exact spawn locations don't seem to be consistent, and it's possible to arrive at the beach too late, and other players have swept away all the fireworks. When you find one, interact with it to turn it on, then interact with it again to throw it. You only need to get one, so it shouldn't take you long if you're heading to the right areas at the very start of the turn.
Once the challenge is over and the round is over, you'll get the 2020 New Years Glider, a nice addition to your ever-growing loot pile.
If you need help with other Winterfest challenges, we've got a full list of challenges and how to complete them. You have until January 7 to wrap them up, because it's the end of Winterfest.