Water Elemental Vortex ability

[ZanThrax]

Do water elementals create vortexes or transform into vortexes?

Water Elemental wrote:

Vortex (Su) A water elemental can create a whirlpool as a standard action, at will. This ability functions identically to the whirlwind special attack, but can only form underwater and cannot leave the water.

Whirlwind wrote:

Whirlwind (Su) Some creatures can transform themselves into whirlwinds and remain in that form for up to 1 round for every 2 HD they have.

And if they're creating a vortex that exists separately from themselves, does it move? How fast? In either case, how big is the vortex?

[Cavall]

The vortex is 5 feet at the bottom and and the rules for width and height are given in the book. Basically you are going to be a vortex for people swimming then you'll enjoy a benefit of having a wide coverage. The downside being that they have to be in water. Some trade offs.

They turn into the vortex. The speeds remain the same like whirlwind.

[ZanThrax]

In that case, what size category is a 20' tall vortex that's 10' wide on the top and 5' wide at the bottom? Large?