They are actually a rare cloud called nacreous clouds or polar ... The stratosphere is very dry-unlike the troposphere (where out weather happens) and it rarely allows clouds to form, so keep ...

Because of the height and temperature needed this cloud is also known as polar stratospheric cloud ... J R Photography They normally form between 12-19 miles (19-31km) high, far above our ...

Nacreous clouds usually form in very cold conditions over polar regions and within the stratosphere, far above our normal clouds. One of the highest clouds, they are often referred to as "mother ...

"Less formation of the polar stratospheric clouds means a limited development ... leads to a colder and stronger polar vortex. The above process would lead to a similar expansion of westerly ...

A cold wave sweeping through the Arctic brought the rare polar stratospheric clouds within ... That's higher than clouds usually form, but at extremely cold temperatures, water vapor can start ...