I saw one of these, over half of Idaho, two weeks ago. I forgot to post about it. It was absolutely massive; I could only see the NE bow-wave of it, the rest went off over the horizons. The center was somewhere off in the SW, towards the coast. Someone was talking about them on a podcast, and reminded me about it.
Man made?
What doesn’t look like on the ground?
It was a enormous arc of a perfect-cemitry cloud-wave front. It arced from the western horizon to the easter horizon, with the whole center clear of all clouds. Like something had detonated on a nuclear level, and then had been expanding for a some time, because the curvature said the epicenter was VERY far away, like perhaps over the next state.
