First of all, congratulations on the peak! It's not every day that a Hail team of all things gets #1 on ladder. This team is very solid as far as Hail goes, with only a couple issues. The first is Choice Band Terrakion
, who can switch in and start spamming Stone Edge with impunity since you don't have a Rock-type resist on the team and every member is either OHKO'd or 2HKO'd after Stealth Rock (Tentacruel dies after 2 Stone Edges + Hail damage even from full HP). Second, Volcarona
is a gigantic threat for this team, as it can get a Quiver Dance off on half your team and net an easy sweep from there. Tentacruel can't hope to hurt it even with a super-effective Scald, because after a QD or two Scald will be doing insignificant damage. However, there is a solution to both these problems. Instead of using your own Volcarona, change it to a Bulk Up Conkeldurr
, which not only resists Rock-type attacks and checks Terrakion, but can take a +1 Fiery Dance or Flamethrower from max SpA Volcarona and OHKO in return with Stone Edge.
252 +1 SpAtk Volcarona Fiery Dance vs 136 HP/120 SpDef Conkeldurr: 63.12% - 74.29%
252 +1 SpAtk Volcarona Flamethrower vs 136 HP/120 SpDef Conkeldurr: 74.81% - 88.31%
That's all I have for you. Again, nice team. Please consider the changes I suggested, and good luck in your future endeavors!