Frost Warding is a mage talent that increases the armor and resistance given by the 
[Frost Armor] and [Ice Armor] spells by up to 50% at max rank 2. In addition, it gives 
[Frost Ward] and 
[Fire Ward] up to 30% chance to negate damage spells that would normally be absorbed (doing no damage to the Ward) and turn the damage they would have caused into mana for the Mage. This talent is useful in both PvP and PvE specs. In PvE it is the most useful talent on its tier after 
[Precision] for a non Frost Mage, and is taken by most Arcane mages for the ability to convert raid damage into extra mana. In PvP, it is useful for extra regen and more protection, with half of the classes having some form of frost or fire spell.
The negation chance is similar to [Molten Shields], which gives [Fire Ward] and [Frost Ward] a chance to reflect spells. Along with 
[Arcane Fortitude], this is one of two Mage talents that will increase armor, though this talent only does so when Ice Armor or Frost Armor is used. The tow are thought to stack additively, so with 2/2 in both talents you would only have a 40% chance to be hit by the warded spell.
Notes
When the negate chance occurs, the damage from the spell is prevented via an absorb, and you are granted mana equal to the amount of damage the spell would have done. This absorb is completely separate from your Ward, and can prevent any amount of damage. Negating Sindragosa's Frost Breath can lead to a gain of over 27k mana, leaving your health bar untouched.
However as the negate effect uses the absorb mechanic, 
[Chaos Bolt] will still deal full damage even if it is negated. When this happens, you gain mana equal to the damage Chaos Bolt deals you.
Patch changes
External links
Patch 4.0.1 (2010-10-12): Removed. 
Patch 1.11.0 (2006-06-19): Added. 
