Ice Block is a core mage ability learned at level 15. It gives short-term immunity to all damage and attacks (except priest Mass Dispel and warrior Shattering Throw), at the cost of being unable to take action. Ice Block also purges most debuffs.
Using Ice Block debuffs the mage with Hypothermia for 30 seconds, which prevents usage of Ice Block during that time. This is only relevant for mages with the Cold Snap talent, which will reset the cooldown for Ice Block. It prevents the mage from casting Ice Block, then resetting the cooldown and immediately casting it again. The effect is similar to the paladin debuff Forbearance.
"Ice Block" is often used as a verb, meaning to use Ice Block to avoid an attack, as in "I Ice Blocked that rogue's Eviscerate." When Ice Block is used to remove a debuff, it is commonly referred to as "Ice Blocking out of ~", as in "I Ice Blocked out of sheep."
Modified by Edit
Casting the spell while you're already Ice Blocked (hitting the hotbar key again) will cancel the spell. It won't cancel itself on a second tap until the global cooldown has finished.
Ice Block removes almost any harmful debuff(s) on caster, even if the caster is not in control of his/her actions. This includes Polymorph and all of a rogue's stuns. Due to the technicality that it "purges" the harmful effect without specifically dispelling it, on-dispel effects like Unstable Affliction's damage and silence will not be triggered. Certain raid-level debuffs are not dispellable by Ice Block, but it will still prevent you from taking damage.
Wearing 4 pieces of Aldor Regalia reduces the cooldown of Ice Block an additional 40 seconds.
With Ice Floes, you can reduce the cooldown of Ice Block to 3 minutes, 20 seconds.
Ice Block is useful for escaping from incapacitating effects and crowd-control spells, waiting for your cooldowns, blocking a large single-hit attack (such as Pyroblast, Eviscerate), or buying time for a healer to heal you.
In a one-on-one battle, Ice Block may give your opponent time to cool down abilities, heal, or run. You should rarely let Ice Block expire on its own, but instead cancel when the timing is right, usually immediately after casting.
Ice Block can be used to avoid fall damage (see Blink and Slow Fall for other ways). While Ice Blocked your character falls normally, but doesn't take any damage when hitting the ground. In previous patches, an Ice Blocked mage would hover in the air, then begin to fall when the spell expired.
Ice Block will prevent drowning and fatigue damage, and reset the damage counter (not the bar) to zero. You will still lose breath and become fatigued while ice blocked.
Ice Block is powerful enough to remove almost any debuff, including Living Bomb or Baron Rivendare's 45-minute debuff (doing so will not prevent you from completing the 45-minute Stratholme run). Some notable exceptions are Resurrection Sickness, Vaelastrasz's Burning Adrenaline, Deathbringer Saurfang's Mark of the Fallen Champion and the Deserter debuff from battlegrounds.
Contrary to popular belief, Ice Block will NOT reduce your current threat level. The reason for this misunderstanding is that enemy AI is programmed to ignore you if you are invincible and move on to the next-highest target on its hate list. As soon as the effect fades the enemy may resume attacking you. However, it will prevent you from performing any actions that generate threat, allowing others (who are still attacking, healing, etc) to rise ahead of you on the mob's hate list. Use Invisibility to remove threat.
It is worth noting that a priest can use Mass Dispel to remove ice block. This may be followed with a Shadow Word: Death for a quick kill if the mage is low on health. Improved Counterspell could be useful here if you manually break ice block while the priest is casting, but act quickly.
Using this macro a mage can instantly stop casting a spell and ice block to protect themselves with no delay. This makes it very useful in PvP or PvE situations which requires you to have fast reflexes to a changing situation.
/stopcasting /cast ice block
For those that have the skill of Herbalism, casting Lifeblood right before Ice Block give your health a reprieve (albiet a low one).
Patch changes Edit
- Patch 2.3.2 (2008-01-08): Ice Block is trainable for mages of all talent builds at level 30.
- Patch 2.3.0 (13-Nov-2007): In Patch 2.3.0, Ice Block was reverted back to its old behavior. Originally, a player who Ice Blocked in midair would continue to fall normally. At one point this was changed so an Ice Blocked player hovered while the spell was active, then began to fall when it expired.
- Patch 2.1.0 (22-May-2007): Hypothermia debuff added. Prior to this, a mage with Ice Block and Cold Snap could be protected for 20 consecutive seconds, with only a short interruption to use Cold Snap.
- Patch 2.0.3 (09-Jan-2007): "Ice block" will now make a mage immune to "Avenger’s shield".
- Patch 1.4.0 (2005-05-05): Fixed race condition where damage would sometimes be applied after Ice Block was activated.