I researched the whole Google, but couldn't find any sufficient information on them. UESP says they should have 40 or 60 pts damage, but most of the times they just simply destroy me with one hit. Strange because I have 110 health +30% frost resist, at least 60 armor (+Breton's magic resist if it counts). I play on master and would happily lower the difficulty but found the entire game quite easy so far, had only a few challenges. So I thought this might be a bug. I'm at the first main quest at College of Winterhold, level 17.
Cheers.