Guardian spirit, pain suppression, sac, ret pally with imp freedom, bop.. There's ways to survive it if you look at videos.
Also unless my math is wrong, the roots will only hit for 15228 which is 9137 (The highest it can hit) with the 60% increased nature damage factored in. It's also nature damage so some of that damage can be mitigated.
Iron Roots
Frost dks in arena do half that much (8k crits with almost 1k resil is fair), and destro locks do 3/5 that much so that's really not that much damage if you look at it in retrospect.