Re: What is this ?
Welcome to the forum - I like the username.
Well the "strange triangular cut out" is the shadow cast by a small hill and the "tanks" are vehicles or maybe cabooses with shadows cast by some structure on top of them (iced-up antenna or exhaust maybe) - and not the gun of a tank!
It just looks like some area of activity, probably by a single vehicle upwind of base possibly to get away from the pollution produced by the base.
UFO crash site?!
I don't think so.