‘You can predetermine a hail storm,’ says forecaster
A forecaster working at the South African Weather Services spoke to the News about the recent storm.
After Krugersdorp saw one of the most destructive storms over the weekend, questions arose about future forecasting of such storms.
The News contacted the South African Weather Services’ (Saws) Senior Forecaster, Jan Vermeulen, and found among other things that the extreme heat of last week did play a role.
“The heat indirectly caused stronger winds, which in turn helped form larger hailstones,” he said.
Jan said the storm that hit Krugersdorp on Saturday also gave a beating to Hartebeespoort all the way to Bela-Bela (also known as Warmbad).
“Forty five millilitres of rain fell in Hartebeespoort,” he added.
Residents in parts of Krugersdorp read more than 50 milliletres of rainfall on Saturday. On Sunday dark clouds once again loomed over the town, but no hail fell.
According to Jan, there is a distinctive cloud that can be associated with a hail storm.
“Mammatus clouds,” he answered.
Mammatus clouds look like they have pouches hanging on the base underneath a cloud.
But strong winds and clouds that form between 16 and 19 kilometres above the ground are good conditions for hail storms. Jan explained that hail forms when clouds are higher. The temperatures higher up in the atmosphere become lower, resulting in water droplets freezing.
“The droplets fall back to the ground but is picked up by strong winds. One droplet then becomes attached to other droplets, forming a big hailstone.”
If wind speeds are not as high, the hailstones are smaller.
Now that the damage is done, you can prevent serious hail damage to you property by following Saws for weather warnings.
The storms are also not entirely unnatural and in March, Saws predicts there will once again be a storm peak.
Read more:
• Town in pieces after hail destruction
• Might of the hail storm caught on camera
• Key West still closed after destructive storm
