Sleet Storm is one of the best spells in the game. I had so much trouble with Halsins portal in my first playthrough and now I just use Gale to Sleetstorm the enemies, Wyll with Hunger of Hadar and my Tav with either AoE spellscrolls or Hypnotic Pattern, depending on what class I play. And Shadowheart just spirit guardians the hell out of everyone coming too close.
