Contrail Shadow

While driving back from work today I noticed that one of the contrails (at the top-right of the screen) was casting a shadow. I watched while I continued driving, and noticed that the shadow moved with the cloud. I’ve not seen a contrail cast a shadow like that before, but maybe there was just enough dust/dirt in the air and I was at the right angle to notice it.

PS – this isn’t an April Fools joke 😉