Fortnite‘s Survive the Storm event is ending on October 2 at 2 AM EDT, and will be replaced with a new Fortnite horde mode. Called Fortnite Horde Bash, the new mode will feature players taking on waves of “escalating challenges.” Details have been scarce so far, but Epic finally opened up about the upcoming mode.
Here’s what executive producer Zak Phelps had to say about the upcoming Fortnite horde mode:
Challenge the Horde will add an instant action wave base defense mode to Fortnite. We wanted to provide more information to help all of you prepare for the Horde Bash event. Please let us know if this primer is helpful.
The Basics:

Fight waves of husks in escalating challenges

Each challenge has 10 waves with mutations
100+ challenges starting at Power 5 and increasing to Power 100 All challenges are made for 4 players and allow each player to use a defender

Build a reusable base

Built prior to starting the challenges
Resources for building are unlocked from the Horde Skill Tree
Horde Points are used to unlock more base building resources

For each challenge you only have your base and your schematics

Each player brings a base to the defense
Each challenge has a strict set of crafting resources
Resources are tiered to the difficulty of the challenge

The Rewards:

29 consecutive quest rewards provide Scavenger Tickets and/or

Choice of a Rare Defender
Choice of Melee or Ranged Epic Scavenger Weapon Schematic
Legendary Scavenger Makeshi...