The image above comes from Spaceweather.com, which describes observations made in Wisconsin on Wednesday. The National Weather Service has a page on “hole punch clouds” that reports earlier sightings and photographs.
It’s interesting when an mage can provoke a nice, simple, “Well, that’s odd.” Particularly when it turns out that scientists, too, have questions about the phenomenon pictured. Evidently, meteorologists “can only speculate on what caused this common but relatively infrequent awesome phenomena to occur.” The speculation involves ice crystals coexisting with supercooled water droplets (still in a liquid state, even though their temperature lies below freezing), but it gets, um, nebulous after that. (Pun intended, I’m afraid.)