Undulatus asperatus (or alternately, asperatus) is a cloud formation, proposed in 2009 as a separate cloud classification by the founder of the Cloud Appreciation Society. If successful it will be the first cloud formation added since cirrus intortus in 1951 to the International Cloud Atlas of the World Meteorological Organization. The name translates approximately as “roughened or agitated waves”.

People in face masks cross a near-empty street after the government announced a state of emergency for the capital and some prefectures following the coronavirus disease (COVID-19) outbreak, in Tokyo, Japan on April 16, 2020. (Photo by Kim Kyung-Hoon/Reuters)

A man and a woman jump over a bonfire during Ivan Kupala Day celebrations held by the Belarusian State Museum of Folk Architecture and Rural Lifestyle in the village of Ozertso near Minsk, Belarus on July 4, 2020. Ivan Kupala Day, also known as Ivana-Kupala or Kupala Night, is a traditional pagan holiday celebrated in eastern Slavic cultures. Various rituals are traditionally performed on Kupala Night, including making flower wreaths, fortune-telling, jumping over bonfires, and burning a wheel-like effigy symbolizing the sun. (Photo by Natalia Fedosenko/TASS)

A taxi driver seen sleeping on his taxi in the middle of a decorated street during the Durga Puja Festival in Kolkata, India on October 22, 2020. (Photo by Avishek Das/SOPA Images/Rex Features/Shutterstock)

The winners of the Historic Photographer of the Year Awards 2020 from triphistoric.com celebrate the places and cultural sites around the world that offer a window to the history that exists all around us. This year, restricted by Covid, photographers were called on to scour their photographic archive to share their imagery of those places that dominate our past. Here: The Brighton Palace Pier. (Photo by Michael Marsh/Historic Photographer of the Year 2020)

A grey heron is seen at the Sempione park, after Lombardy was downgraded from a red to an orange zone, loosening the coronavirus disease (COVID-19) restrictions including allowing non-essential shops to re-open, in Milan, Italy, April 13, 2021. (Photo by Flavio Lo Scalzo/Reuters)

Volodymyr, a service member of the Ukrainian armed forces, plays with puppies at fighting positions on the line of separation from pro-Russian rebels in Donetsk region, Ukraine on April 10, 2021. The two unnamed puppies living on frontline positions will be taken home and named by soldiers departing on troops rotation. (Photo by Oleksandr Klymenko/Reuters)

Blindfolded Myanmar boys try to eat the biscuits during a fair on the occasion of the 73rd Myanmar Independence Day in Yangon, Myanmar, 04 January 2021. Myanmar, also known as Burma, was colonized by Britain in 1824 and became an independent republic on 04 January 1948. (Photo by Lynn Bo Bo/EPA/EFE)