While making another attack, you attempt to blind a foe with thrown sand.
Prerequisites: Wis 13, Tumble 4 ranks.
Benefit: In any round when you first move at least 10 feet using your Tumble skill in an area covered in a layer of at least 1 inch of ash, dust, loose earth, or sand, you can supplement an attack made in that same round with flung or kicked material. A foe damaged by your attack must make a Fortitude saving throw (DC 10 + ½ your character level + your Wis modifier) or be blinded for 1 round.
See Determining Loose Soil for finding the chance of sufficient ash, dust, grit, loose earth, or sand existing to use this feat.
Source: Sandstorm, page 52.