|
No, once it's active, it remains active until the character deactivates it or the duration ends. Since it's a supernatural ability, it can't be disrupted by combat, so it makes me think it does not require the character to concentrate to maintain it. The character could deactivate the gale aura as a free action.
Even though the text uses the term "gale-like winds", which normally would mean close to gale force winds like a hurricane, I think this is more along the lines of a severe strength wind (31-50 mph; Core Rulebook pg. 449) on par with a gust of wind spell. It's not strong enough to force a Strength check from a Medium creature to advance, but it can slow their advance.
As an additional property of the ability, it could likely extinguish unprotected flames like torches and impose a -2 circumstance penalty to ranged attacks, but that's up to the individual GM. Most don't like giving additional powers to abilities that aren't enumerated in the ability description.
Does the Gale Aura from Storms Subdomin (APG) require an action to maintain each round?
No, it costs a standard action to turn on and it stays on until you turn it off.
What level of winds are these winds considered? Strong, Severe, Hurricane, Tornado?
None and irrelevant. It is considered its own specific effect that is explicitly detailed (no 5 foot steps, difficulty terrain when moving towards you, etc.) and has nothing to do whatsoever with wind levels. It does exactly that and only that, and does not interact with any other ability that relies on wind or modifies wind or anything else.
Do these effects affect the cleric they are originating from?
Duh...I mean specifically the 5 foot step?