COVID-19 is a contagious disease caused by the coronavirus SARS-CoV-2. In January 2020, the disease spread worldwide, resulting in the COVID-19 pandemic. The symptoms of COVID‑19 can vary but often include fever,[7] fatigue, cough, breathing difficulties, loss of smell, and loss of taste.[8][9][10] Symptoms may begin one to fourteen days after exposure to the virus.…

Snow begins as ice crystals that form and grow in cold clouds. Their shapes depend on the conditions they encounter, including temperature and the availability of water vapour. Crystals can join together as they fall, producing flakes of different sizes. What reaches the ground may be light and powdery, dense and wet, or somewhere between…