Arcane Blast is a mage ability learned at level 10 for those who have chosen the Arcane specialization. It deals direct arcane damage, generating an [Arcane Charge] each time. So long as one charge remains active, it increases both the damage and cost of the spell. With careful management, the mage can use this spell to trade off damage per mana versus damage per second.
Patch 5.2.0 (5-Mar-2013): Arcane Blast's damage has been reduced by 22.9% and mana cost has been increased to 1.66667% of base mana (was 1.5%).
Patch 4.2.0 (28-Jun-2011): Arcane Blast damage done has been reduced by 5%.
Patch 4.1.0 (26-Apr-2011): Arcane Blast cast time has been reduced to 2.0 seconds, down from 2.35 seconds. In addition, the stacking effect of Arcane Blast now increases the damage done by Arcane Explosion, and Arcane Explosion does not consume that effect.
Patch 4.0.6 (8-Feb-2011): Arcane Blast mana cost has been reduced by 12%.
Patch 3.2.2 (2009-09-22): The buff from using this ability now stacks up to 4 times instead of 3, and each application increases mana cost by 175% instead of 200%. In addition, the duration of the buff has been reduced to 6 seconds.
Patch 3.1.0 (14-Apr-2009): Stacking effect is no longer considered a Magic effect and will not be dispelled. Formerly it was considered a harmful magical effect and would be dispelled by friendly casters, sometimes by accident, other times because of other magic debuffs.
Patch 3.0.8 (2009-01-20): This ability has been significantly changed. Arcane Blast now increases the damage of the next Arcane spell by 15%. However, using Arcane Blast itself does not consume the charge itself. Each time you cast Arcane Blast, the damage of Arcane spells is increased by 15% and the mana cost of Arcane Blast is increased by 200%. This effect stacks up to 3 times and lasts 10 seconds or until any Arcane damage spell except Arcane Blast is cast.
Patch 3.0.3 (04-Nov-2008): Reduced the mana cost of Fireball, Frostbolt, Frostfire Bolt, Arcane Blast, Arcane Missiles, and Arcane Explosion.
/Patch 3.0.2 (14-Oct-2008): The debuff was changed from a cast time reduction to a pure damage increase, and the mana cost penalty was massively increased. Arcane Blast effect duration reduced to 3 seconds from 8, and now increases damage by 25/50/75% instead of reducing cast time.
Patch 2.1.0 (22-May-2007): The Arcane Blast debuff can no longer be dispelled.
Patch 2.1.0 (22-May-2007): A data error was fixed that was causing Arcane Blast to generate more threat than intended.
Patch 2.0.3 (09-Jan-2007): The mage spell "Arcane Blast" will now receive the mana reduction benefits from "Clearcasting".