The Doppler on Wheels (DOW) vehicle scans a supercell thunderstorm during a tornado research mission, May 8, 2017 in Elbert County near Agate, Colorado. Doppler on Wheels (DOW) is a mobile doppler radar mounted on a truck that brings instruments directly into storms, allowing scientists to scan storms and tornadoes and make 3-D maps of wind and debris. (Photo by Drew Angerer/Getty Images)

North Korean soldiers wave along the Yalu River, near the North Korean town of Sinuiju, opposite to the Chinese border city of Dandong October 7, 2014. (Photo by Jacky Chen/Reuters)

Snow falls as a woman walks her dog in the village of Podolye, 70 kilometers (43 miles) east of St. Petersburg, Russia, early Thursday, May 11, 2017. North winds brought snow to the east of the St. Petersburg region. (Photo by Dmitri Lovetsky/AP Photo)

Children, wearing red neckerchiefs, a symbol of the Pioneer Organization, salute during a ceremony for the inauguration of 18 new members at a local school in the southern settlement of Kazminskoye in Stavropol region, Russia, November 19, 2015. Early pro-communist youth movements, which appeared in Russia after the 1917 Bolshevik revolution, were reformed into the Pioneer Organization of the Soviet Union. While the organization lost its dominance among students in post-Soviet Russia, some educational institutions and families still carry on this tradition. (Photo by Eduard Korniyenko/Reuters)

Finding just the right spot above the clouds at Camp 1 on Ama Dablam, Danuru Sherpa uses his iPhone to catch up with friends and family. Even at 18,500 feet (5,654 meters), climbers here can check their email and other dispatches from the world below. (Photo by Aaron Huey/National Geographic)

In this photo taken on Saturday, May 2, 2020, funeral workers, wearing protective suits, lower the coffin of Semen Muchka, 71, who died of coronavirus disease, into the grave at a cemetery in Krynytsya, Ukraine. (Photo by Evgeniy Maloletka/AP Photo)

A woman wearing a face mask to help curb the spread of the coronavirus gets fever checked before going into the Pyongyang Railway Station in Pyongyang, North Korea, Thursday, August 13, 2020. (Photo by Jon Chol Jin/AP Photo)

A woman takes a selfie picture at the Poklonnaya Hill in western Moscow near the main building of the Moscow State University on June 17, 2020, as the air temperature approaches 30 degrees Celsius. (Photo by Alexander Nemenov/AFP Photo)