Monsters

A medium-size air elemental is 8 feet high and weighs 2 lbs.

Air elementals speak Auran, although they rarely choose to do so. Their voices sound like the high-pitched screech of a tornado or the low moan of a midnight storm.

Combat

Elemental: Immune to poison, sleep, paralysis, and stunning. Not subject to critical hits.

Air Mastery (Ex): Airborne creatures suffer a -1 penalty to attack and damage rolls against an air elemental.

Whirlwind (Su): The elemental can transform itself into a whirlwind once every 10 minutes and remain in that form for up to 1 round for every 2 HD it has. In this form, the elemental can move through the air or along a surface at its fly speed. The whirlwind is DC 13, damage 1d6, and height up to 30 feet.
The whirlwind is 5 feet wide at the base, up to 30 feet wide at the top, and up to 50 feet tall, depending on the elemental's size. The elemental controls the exact height, but it must be at least 10 feet.
Creatures one or more sizes smaller than the elemental might take damage when caught in the whirlwind (see the following table for details) and may be lifted into the air. An affected creature must succeed at a Reflex save when it comes into contact with the whirlwind or take the listed damage. It must also succeed at a second Reflex save or be picked up bodily and held suspended in the powerful winds, automatically taking the listed damage each round. A creature that can fly is allowed a Reflex save each round to escape the whirlwind. The creature still takes damage but can leave if the save is successful. The DC for saves against the whirlwind's effects varies with the elemental's size.
The elemental can eject any carried creatures whenever it wishes, depositing them wherever the whirlwind happens to be. A summoned elemental always ejects trapped creatures before returning to its home plane.
If the whirlwind's base touches the ground, it creates a swirling cloud of debris. This cloud is centered on the elemental and has a diameter equal to half the whirlwind's height. The cloud obscures all vision, including darkvision, beyond 5 feet. Creatures 5 feet away have one-half concealment, while those farther away have total concealment. Those caught in the cloud must succeed at a Concentration check to cast a spell (DC equal to the Reflex save DC).