User blog comment:Jimeee/Skyrim 1.9 beta update adds Legendary difficulty and raises level cap (Updated Apr 8th)/@comment-31.53.78.34-20130413223835/@comment-1840877-20130414081341

Can't speak for them, since I've never encountered them. But I do know that frost dragons are downright lethal, and that trying to tackle them head-on is often suicide.