It came as a surprise to the people of Gozaki ward, in Kafur Local
Government Area. of Katsina state when they saw ice falling from the sky instead of the usual rain that has been falling in the last couple of weeks.
However the Nigetian Meteorological Agency, NiMet, in a release described the unusual precipitation event that occurred on the 11th of September 2022 as hailstorm.
“The event of 11th September 2022 over parts of Katsina state, was a
case of hailstorm, a rare weather phenomenon which has also been reported in other parts of northern Nigeria recently.”.
The release indicated that satellite imagery obtained from PUMA showed the presence/formation of cold clouds (Cumulonimbus) over the south-eastern parts of Katsina around 1400UTC , the clouds had grown into a super cell thunderstorm, covering most parts of the state, between 1200UTC and 1300UTC and remained over there for a couple of hours. The system propagated westwards from there, affecting Zamfara, Sokoto and Kebbi States before exiting the country.
A hailstorm is a weather phenomenon in which balls of ice, called hail, fall from the sky. A hail can be formed at high altitude in the atmosphere within massive clouds, when supercooled water droplets adhere to each other and form layers of ice balls.
These ice balls are solid precipitation that are usually formed under certain conditions in the atmosphere, such as:
1. The presence of a highly developed Cumulonimbus clouds (super cell thunderstorms).
2. Strong currents of air ascending (updraft) through these clouds.
3. Clouds with high concentrations of supercooled liquid water.
A hailstone begins as a water droplet that is swept up by an updraft inside of a cumulonimbus cloud over an area.
Supercooled water droplets/particles present in the clouds adheres to the water droplet’s surface, forming layers of ice around them. As the water droplet reaches higher elevations within the clouds, where the cloud temperatures are often less than -60oC, they encounter more and more supercooled particles and grow larger as the updraft continues. Eventually, gravity begins to act on them, pulling it down and thus the occurrence of hailstorms over the area.