User blog comment:VedranTheII/Pretentious Diaries 2: What tricks would you teach your Aura?/@comment-5217560-20150719083609/@comment-25555436-20150719144204

I figured she just used Dust, not needing to throw it into the sky.

I mean, Cinder was able to cause an eruption on the ground, far away from herself, without having to throw anything anywhere. It's only logical Glynda was able to do the hailstorm by also using Dust without havin to throw it anywhere, only in her case she manifested the attack on the sky, and towards the ground.