An unusual weather phenomenon occurred in the Dongcheng District of Beijing, China, on July 28, 2020. According to residents, it appeared like white snowflakes that fell in the area during a hot summer day, but meteorologists said it might be "chal" or graupel.
At around 07:20 UTC (15:20 LT), residents in Dongcheng were taken aback by a bizarre phenomenon as pellets that looked like snowflakes suddenly fell amid the summer season. The event lasted for five to six minutes.
A resident named Mr. Li took a video of the unexplained weather event and posted it on social media, causing a stir among his friends and other viewers on whether it was indeed snow or another occurrence.
According to Chinese media outlet The Paper, meteorologists believe it might be "chal" or graupel, frozen white precipitation resembling hail.
大熱天的北京竟然飄雪？7月28日下午3時20分許，家住東城區春秀路的網友拍下異常景觀，白色的雪花紛紛揚揚，這種奇妙的現象持續了五六分鐘 。時下正是大熱天，突然下雪堪稱奇觀。 pic.twitter.com/65qWrvtVnN— 小婷 (@ttingxiao) July 30, 2020
The Chinese Communist Party's official media, quoting experts, said it was indeed soft hail, which tends to appear in strong convection in summer.
Graupels are white and opaque cooled water droplets that are soft and easy to crush.
Snow crystals may encounter supercooled water droplets under certain atmospheric conditions. These droplets can exist in a liquid state at temperatures below the freezing point.
Interaction between a snow crystal and supercooled droplets results in the freezing of liquid droplets onto the surface of the crystal in a process called accretion.
Crystals that appear as frozen droplets on their surfaces are usually referred to as rimed. When this process continues so that the original snow crystal's shape is not identifiable anymore, the resulting crystal is referred to as graupel.
The difference between hail and graupel is that hail forms in hard, uniform layers and usually falls during thunderstorms, while the latter is fragile enough that it can be pulverized when touched.
Featured image credit: China Actual/YouTube