Empty the Warrens | Magic: The Gathering
Formats Empty the Warrens is Legal in
Official Oracle Text for Empty the Warrens
Storm (When you cast this spell, copy it for each spell cast before it this turn.)
—Sarpadian Empires, vol. IV
Official Rulings for Empty the Warrens
6/7/2013 : Spells cast from zones other than a player's hand and spells that were countered are counted by the storm ability.
6/7/2013 : A copy of a spell can be countered like any other spell, but it must be countered individually. Countering a spell with storm won't affect the copies.
6/7/2013 : The triggered ability that creates the copies can itself be countered by anything that can counter a triggered ability. If it is countered, no copies will be put onto the stack.