Polar clouds over Peru

    

Stunning polar stratospheric clouds were captured by David Alvarado over Lamas, in the region of San Martín, Peru on January 18, 2018.

Polar stratospheric clouds, also known as nacreous clouds (or mother of pearl, due to its iridescence), are clouds in the winter polar stratosphere at altitudes of 15,000-25,000 meters (49,000-82,000 ft). Usually the clouds only form over the poles during winter because the air in the upper stratosphere needs to be at least -78C.

These images were posted on Red Climática Mundial (Global Climate Network).

Polar stratospheric clouds over Peru

    

Polar clouds over Peru

    
Polar clouds over Peru

    

This ‘rare’ phenomena is becoming increasingly common:

Though beautiful, these clouds are likely an indication of a cooling atmosphere, due to dust loading from increased comet and volcanic activity.

For some other indicators see these related articles: