Larian Studios Forums Divinity - Original Sin Divinity Original Sin - Help/Tips/Tricks Summation of the Spell Combo Possibilities

There's also a combination in the same school. Water + "ice" (winterbreath I think) will make frozen ground that you can slip on. Or hitting someone that is wet or chilled with ice shard or piercing ice shard will also leave some residue on the ground on which you can slip too (edit: I think it'll leave some ice on the floor regardless of the status inflicted on the enemy, he might as well not be wet or chilled and it'll leave a small portion of the ground frozen).

Not exactly what you wanted but it's also useful.