Frost Nova

Frost Nova is a point-blank area of effect spell that does light damage and freezes all enemies within 10 yards of the mage, rooting them in place for 8 seconds. Rooted enemies have a chance to break out each time they take damage; this check is made every time damage is dealt from any source.

Table
Frost Nova is available at level 8 for.

Talents
The Ice Floes talent will reduce the cooldown to 20 seconds at max rank. Cold Snap will simply finish its cooldown. The Glyph of Ice Block also resets its cooldown every time the mage uses Ice Block.

Arctic Reach talent will increase the radius of Frost Nova to 12 yds.

Elemental Precision and Frost Channeling reduce the mana cost of the spell, while Frost Channeling also lowers its threat. Frost Nova deals Frost damage, so the bonuses from Piercing Ice, Ice Shards, Arctic Winds and Winter's Chill apply to the spell. Master of Elements will refund a percentage of the mana cost of the spell if it critically hits at least one target.

As with all mage spells capable of critical hits, Arcane Instability, Spell Power, Molten Fury, Playing with Fire, and Shatter can increase the effective damage output of this spell.

As of Patch 3.0.2, Impact from the Fire talent tree will work with Frost Nova.

Glyphs

 * Glyph of Frost Nova
 * Glyph of Ice Block

Tips and tactics
Use Frost Nova to root enemies in place and then gain some range to cast spells without getting hit. This is especially effective against melee-only enemies, as they will not have any other way to attack you. Against caster-type enemies, use Frost Nova to gain range along with Counterspell to interrupt their casting. Also use Frost nova to root enemies that you may have pulled off the tank, and allow them to regain aggro.

Frost Nova is an important ability in frost talent specs that use Shatter, as it is a guaranteed freeze effect. The Shatter talent works on any target rooted by one of your frost spells. With Frostbite fully upgraded, any cold spell that snares has a 15% chance to root. Frost Nova, on the other hand, will always root, guaranteeing you can Shatter away with your next cast.

All ranks of this spell root the target(s) in place for the same amount of time and with the same resistance rates, and spell damage is never very much. Prior to Patch 3.0.2, some magi opted to always use the first rank due to the lower mana cost. However this is no longer an effective strategy as all spells are calculated as a percentage of base mana. Prior to Patch 3.3.0, this is especially true as spells under level 70 suffered from an increased mana cost compared to their higher level equivalents.