What caused Monday night’s storm damage?
LADSON, S.C. (WCBD) – Hail, strong wind, and damage accompanied a thunderstorm that moved through the Summerville area Monday evening.
Many were left wondering if a tornado struck the area due to the intensity of wind that caused damage, toppled trees, and dumped hail in a radius from Summerville to Ladson and Goose Creek.
Storm Team 2 forecasters say what people likely experienced was a downburst.
“Tornado damage is going to be very narrow; it’s going to be very confined,” said Storm Team 2 Meteorologist Josh Marthers. “You are looking at large swaths of wind damage which is a signal of downdraft winds, essentially a storm collapsing – all of the rain, wind, and hail hits the ground and spreads out in all directions.”
He explained that in a tornado, wind converges while straight-line wind diverges – which is what we saw last night in the Summerville area. Marthers was able to show that data on Storm Team 2 VIPIR Radar.
The storm wind mode shows us the direction winds are moving inside a thunderstorm. Green indicates winds moving toward the radar while red is wind moving away.
7:35 p.m.: there is a large area of red moving away from the radar towards Summerville.
7:40 p.m.: we see that area of red moving into Summerville.
7:40 p.m. – 7:45 p.m.: There is a bright red spot over Summerville, near Ladson, and then a bright green spot just behind it. It tells the picture of the diverging wind.
“That’s why we had all the large hail reports, all the wind damage reports, and they were right in that fairly large area,” said Marthers.
“We think it was what we call a downburst. Keep in mind these storms grow vertically in the atmosphere. They are held up by what we call a strong updraft. When you start to see those clouds build, that was that updraft pushing that cloud up. It was also taking water droplets from the bottom of the cloud to the top of the cloud where the temperature is below freezing – and then a downdraft brought it back down,” explained Storm Team 2 Chief Meteorologist Rob Fowler.
Eventually that icy crystal got a little bigger, and then a little bigger, and that was the hail. We had a strong updraft pushing that could up, then what happened was once you had the hail and the rain, we started to see that cold air start to sink, and that caused a downdraft.
He explained that when you get a downburst, it indicates there could have been a tornado because of damage, but you have to look at which way the trees fall. Do they fall in the same direction, or do they fall more in a rotation?
The storm caused trees to fall on many homes in the area, knocking out power to thousands of utility customers. Berkeley County officials have been assessing damage and working to clear trees from roadways. If you have damage in the county, you are asked to report it online.
