Pet Cloud reappeared above your favorite spot in New Zealand

Science: A strange “pet cloud” played a starring role in a recent satellite image of New Zealand. The peculiar structure often appears in the same location because of a nearby mountain range — and is sometimes mistaken for a UFO.

Known by locals as the “Taieri Pet,” this thin oblong cloud is an elongated altocumulus standing lenticular cloud (ASLC) that often appears between the towns of Middlemarch and Hyde in the Otago region of New Zealand’s South Island. Although they can vary slightly in shape, the clouds always look very similar and appear in roughly the same location. The example shown in this image is about 7 miles (11.5 kilometers) long.

According to the National Weather Service, ASLCs form when air waves pass over a topographic barrier, such as a mountain range, causing water vapor to condense in vertical layers. According to NASA’s Earth Observatory, the Taieri Belly forms when moist air passes through the mountainous Rock and Pillar Ranges (located parallel to the left of the cloud in the photo) and is held in place and further shaped by perpendicular winds blowing from the north. “When the cloud forms at the crest of this wave, it remains nearly stationary in the sky and is shaped by the strong winds blowing through it,” John Law, a meteorologist at MetService New Zealand, told Earth Observatory.