This photo of a lenticular cloud was taken over the Macraes mine in East Otago on Sunday, by Air New Zealand First Officer Geoff Beckett, who was on the flight deck of an ATR-600, flying to Dunedin.
"We commonly refer to them as a pile of plates.
"I’ve been flying for 20 years now and I’ve never seen anything like that. It’s the best example I’ve ever seen.
"The scale of it was huge. It just kept going up and up and up.
"The image makes me think of a massive alien mothership."
Mr Beckett said the flight deviated to avoid flying through the turbulent cloud.
"These cloud types are notoriously dangerous to even powerful commercial aircraft.
"As we deviated to the right to go around it, it turned out to be a surreal sight indeed."
MetService meteorologist Tom Adams said lenticular clouds were formed by strong northwesterly winds blowing over the Southern Alps.
"You basically get a standing wave when the wind goes over the mountains. That is, the air is descending, then rising, then descending again.
"These clouds form where the standing wave is rising and the air is cooling, therefore water is condensing and you get clouds.
"Often, with these lenticular clouds, you’ll get a sequence of them."
