Models take part in the promotion of the Miss Bumbum (buttocks) beauty pageant, along Paulista Avenue in Sao Paulo, Brazil, on August 7, 2017. The annual Bumbum pageant to select the nation' s sexiest female buttocks will be held on November, 6 in Sao Paulo. (Photo by Nelson Almeida/AFP Photo)

In this image taken with a slow shutter speed, Slovakia's Emma Zapletalová competes in the women's 400-meter hurdle race during the Bislett Games athletics meeting at Bislett Stadium in Oslo, Thursday, June 12, 2025. (Photo by Fredrik Varfjell/NTB via AP Photo)

Revellers get into the spirit of the 40th annual Zomercarnaval – summer carnival – in Rotterdam on July 28, 2024. The two-day event is such in integral part of Netherlands tradition it was added to Unesco’s Intangible Cultural Heritage list last year. (Phoot by James Petermeier/ZUMA Press Wire)

Israelis in costumes spray water on each other during the annual Tel Aviv Water War on Hbima Square in Tel Aviv, Israel,10 July 2015. The annual water fight is on his 11th edition. (Photo by Abir Sultan/EPA)

Two couples prepare to pose for their wedding pictures outside the Forbidden City in Beijing on October 31, 2022. (Photo by Wang Zhao/AFP Photo)

Tourists visit an art installation of colorful umbrellas on November 10, 2022 in Nanjing, Jiangsu Province of China. (Photo by VCG/VCG via Getty Images)

A child enjoys yellow gingko leaves outside the Diaoyutai State Guesthouse on November 8, 2022 in Beijing, China. (Photo by Zhao Jun/China News Service via Getty Images)

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”.