Intense Cold

Intense Cold is a dungeon & raids achievement earned for defeating Keristrasza in the Nexus on heroic difficulty without allowing Intense Cold to reach more than two stacks.

Strategy
Movement breaks Intense Cold, so just keep strafing/jumping/moving, and avoid spells with long cast times. If you get rooted by Crystal Chains, use Free Action Potion or PvP trinket or whichever class/racial abilities you have to get out of movement-impairing effects. If you have a priest in the group, have all group members stand close to each other and use Mass Dispel.

Trivia
Higher leveling characters attempting to solo this achievement should ensure that Intense Cold is cast before killing Keristrasza, since killing her before she can cast Intense Cold will not give you the achievement.