Heroes of the Storm will launch on June 2, 2015, with open beta testing starting on May 19! Visit the official website for even more information on the game.
As for wipes, there will be none for purchases and progression accomplished during closed beta. They will carry on through open beta and post-launch.
Below is the official announcement from the website:
It’s been a jam-packed year for Heroes of the Storm, and now it’s time to rally your fellow heroes and get ready for battle, because the portal to the Nexus is about to burst wide open! We’ve just announced that Blizzard’s worlds will collide when Heroes of the Storm™ officially launches on June 2, following an open beta testing period that begins on May 19.
The Heroes of the Storm open beta test will follow on the heels of the epic finale of the Heroes of the Dorm™ collegiate eSports tournament. Students from more than 400 schools across the U.S. and Canada have bashed and brawled their way through the brackets, with more than $450,000 in tuition and other prizes up for grabs. On April 26, the final teams will face off at the Heroes of the Dorm championship match, which will be hosted at the Shrine Auditorium and Expo Hall in Los Angeles and televised live in prime time on an ESPN network and also accessible via WatchESPN—further details on the telecast will be announced at a later date.
For more information on this live event and how you can attend in person, please dive into our Heroes of the Dorm blog.
We will not be performing any further wipes, so any current progress or purchases you’ve made thus far during closed beta will carry through to open beta as well as post-launch. If we determine later down the line that our progression system needs to be modified, progress will not be wiped, but will be assigned to the appropriate Hero and/or Player level.