Death House for Curse of Strahd, Wizards of the Coast has released the first chapter of Storm King's Thunder entitled A Great Upheaval. This will take starting characters from level 1-5 (though that seems like a lot of levels for just a few pages). The adventure also contains new monster stats, the tressym.
Honestly, this is a great marketing idea for WotC. Give players a taste of the adventure.
It will be a bit before I buy a copy of Storm King's Thunder, but the copy I reserved through the library is in processing now. I may or may not run the adventure, but I'm still excited to read it. If you're going to run it, you should check out my suggested side quests.