Target: each creature in the area of effect
Attack: Intelligence vs. Fortitude
Hit: "1d6 + Intelligence modifier thunder damage, and you push the target a number of squares up to your Wisdom modifier.
"Level 21: 2d6 + Intelligence modifier thunder damage."[PH:159][Dr401:53]
Thunderwave is an at-will power available to wizards at 1st level.
The "Class Compendium: The Arcanist" article in Dragon 401 added the evocation keyword to thunderwave.