The grass suggest two things in that vid. First, it is inclined (bent) toward the water which suggest prevailing air movement in that direction. Second, if you look at the first frames you can see it bouncing in the direction of the sea. The bear is about 45-60� from them at the first shot so he wouldn't scent them. However, after he is hit, and around the moment of the second shot, he appears to be downwind almost directly.
Bears' olfactory senses are dominant and are probably what triggered his 'locator beacon'
