The plane of quasielemental steam is not a hot plane, though portions of it are on the verge of boiling. Mist may be a better name - clammy, thick, cloying mist that seeps into everything. The danger here isn't boiling, but drowning in lungfuls of water.
Near the edge of the plane of Elemental Water, the mist is more like an ocean filled with bubbles. As a swimmer from Water's great ocean slowly finds the world spreading on him, the bubbles join and the water forms freefloating droplets. These gradually become finer and finer, and they glow with energy stolen from the Positive Energy Plane.
Just at the border to the Positive Energy Plane stands the glowing Tower of Ice, a glittering spire that lances upward almost as far as can be seen. Who or what built this tower is unknown, but alchemists sometimes come here to complete essential steps in potion brewing.