Just went up against Malkoran and was somewhat surprised at the effectiveness of his frost spell.

My character is a Breton mage with 65% magic resist (Breton+Mara+Lord Stone) and 325 HP. One hit with his Ice Storm spell, however took my health down something like 200 points (playing on master). I am having a hard time seeing this.

Ice Storm has a base damage of 40. Augmented Frost rank 2 would bump that to 60. Dual cast (I don't know if Malkoran dual casts) would be 132. Adjustment for difficulty level would be 264. Adjustment for magic resistance would be 92, or about one third of my health. But he easily took it down by two thirds.

Also, I cast Mayhem before actually facing Malkoran and I watched as he one-shot killed the corrupted shades with his ice storm.

I've looked on the uesp wiki for info on Malkoran and even though it mentions his "powerful frost spell" it does not provide any details. So my question is: does Malkoran use a special type of Ice Storm?