MTG Salvation

9/22/2011 If the land is an illegal target when Tectonic Rift tries to resolve, Tectonic Rift won’t resolve and none of its effects will happen. Creatures without flying will be able to block as normal.

9/22/2011 The set of affected creatures isn’t locked in when Tectonic Rift resolves. Creatures without flying that enter the battlefield later that turn or creatures that lose flying later that turn won’t be able to block.