While the supernatural ability wind blast is not a spell, this GM thinks it safe to treat the ability as one if the wind blast's user takes the ready action and picks the action use wind blast and the trigger when that dude starts casting.
In fact, this GM tends to read the section on Spells (see below) broadly, allowing any extraordinary, spell-like, or supernatural ability to be used in a manner similar to spells to distract casters. On Magic on Concentration on Spells says
if you are affected by a spell while attempting to cast a spell of your own, you must make a concentration check or lose the spell you are casting. If the spell affecting you deals damage, the DC is 10 + the damage taken + the level of the spell you’re casting.
If the spell interferes with you or distracts you in some other way, the DC is the spell’s saving throw DC + the level of the spell you’re casting. For a spell with no saving throw, it’s the DC that the spell’s saving throw would have if a save were allowed (10 + spell level + caster’s ability score).
(Emphasis mine.) Certainly, a raging blast of wind is capable of distracting the caster! As the supernatural ability wind blast is unique therefore not possessing a spell level and since it was acquired at level 1, this GM would, for the purposes of distracting casters, consider the supernatural ability wind blast the equivalent of a 1st-level spell, but ask your GM.
All in all, it's pretty safe to read that Spells section as Special Abilities and Spells rather than as Spells alone. It doesn't make sense1 that a wizard could cast normally while affected by the supernatural ability wind blast yet must make concentration checks if affected by the spell gust of wind.
That said, this GM would have the caster make a concentration check (DC 11 + the user's ability score) to avoid losing the spell due to the supernatural ability wind blast as the effect typically doesn't allow a saving throw.
"Why not just use the concentration check DCs for something other than spells when using wind blast?"
In the case of concentration checks, the game seems to care more about an effect's source than an effect's result. That is, were a caster interrupted by the spell gust of wind, then the caster makes a concentration check against that spell's DC and not against, for instance, the concentration check against "wind-driven hail, dust, or debris" (which is also lower than the DC for a spell at DC is 10 + level of the spell the caster's casting).
And while violent motion includes "being pitched roughly" as if one were "on a galloping horse, taking a very rough ride in a wagon, on a small boat in rapids or in a storm, on deck in a storm-tossed ship," the caster still makes a concentration check instead against a spell's DC if affected by a spell even if the spell's result resembles one of those effects.
Basing the concentration check for special abilities other than spells on results rather than effects means the GM evaluates each effect and categorizes them himself arbitrarily, which this GM can see having unintended consequences like overpowered but low-level effects, underpowered high-level effects, and unhappy players.
1 I don't typically use the It doesn't make sense argument because usually, to somebody, it does make sense. I'm not sure who that individual would be in this case, but I look forward to that answer.