Just a heads up for those not already in the know.
Greater creeping cold (i assume the lesser one too, but not tested that one) cancel out wizard/sorcerer Niacs biting cold dot. If this is WAI its bloody stupid as more than one wiz/sorc can dot mobs with niacs and they don't cancel each other out.
So in essence casting greater creeping cold when you have a wiz or sorc doting mobs with niacs does not make them happy bunnies. Yes, that's right kiddies makes druids even more useless against raid bosses.