About 1/3 of the way into the image from the left, you can see the little gustnado kick up dust underneath beastly structure.
On June 17th, 2017, a prominent shelf cloud came ashore and traveled towards Mitchell, Ontario. I was right on the edge of it. You can see the "teeth" as they draped down towards me.
Not a lot of upper level winds to prevent this monster from becoming a high precipitation storm.