I don’t know what to believe. My hunch says probably just a jet contrail but I’m no expert so do I listen to the “experts” or to the convinving people posting here? From the pic on the last page comparing 2 side by side the one on the left looks vertical to a degree but then you can tell at second glance that it’s just the disappearing horizon. However the photo on the right (the one in question) seems to clearly show vertical. There is too much dense smoke at the base. It appears to be very close to the “lift-off” point and proceeding upward. And if it was disappearing horizon you wouldn’t see the slight curve?
Well, the only expertise I have is being a Forward Air Radarman with access to Silos at Malmstrom and Launches from Vandenberg. Outside of that, anything needing Arizona ranges went through me. The Army in Fayetteville probably didn’t need my help. My Family was kind enough to keep me posted. :^)