Originally Posted by Aphyrax

Arcane blast has not been updated yet on the official site, but the latest numbers for a fully wound up blast are:

1.5 second cast time
700 average damage
488 mana

It takes 3 casts to get there. At those numbers, the DPM is not terrible. Frostbolt (pre channeling) has a base DPM of 1.878 at max rank, arcane blast has 1.434. What makes the spell interesting is that it outscales every other mage spell since it gets a 2.5 second damage bonus for 1.5 second cast.