P.S.--When was the photo taken? I used to fly out of Auburn, so I know the "where".
Are they also not filled with ice?They look menacing but they really aren't. They ARE often associated with nearby menacing weather but regularly occur in benign conditions. A sky full of them at sunset during tornado season in the midwest is awesome. You can fly around under them all day with little risk as long as you are far enough away from the updraft and the hail and the lightning