My first photograph of this feature.  I used my fisheye lens so that I could record as much of the cloud as possible.    The view is from 13th street looking west.  At this point it did not appear to be moving that fast towards me.  It still appeared to hug the horizon. (6:25 a.m.)

I'm now on Highway 136 driving to the west.  This cloud appeared to extend infinitely off into the south as well.  I was becoming concerned because all of my photos so far were taken with a fisheye lens and in a moving truck.  I wanted to get somewhere to take some steady shots. (6:26 a.m.)