UberNZ:
My guess would be lenticular clouds. Moist non-turbulent air blows over a hill, the air cools as it gets lifted, which makes the moisture precipitate as a cloud. It appears to stay still, and the shape resembles a stack of lenses.
You need just the right terrain, moisture, a bit of breeze, but not a lot of shear ... it's pretty rare. It also looks freaky as f**k, so a lot of UFO sightings can be traced back to lenticular clouds.
My guess would be lenticular clouds. Moist non-turbulent air blows over a hill, the air cools as it gets lifted, which makes the moisture precipitate as a cloud. It appears to stay still, and the shape resembles a stack of lenses.
You need just the right terrain, moisture, a bit of breeze, but not a lot of shear ... it's pretty rare. It also looks freaky as f**k, so a lot of UFO sightings can be traced back to lenticular clouds.