Ninety-seven years ago today was the most devastating tornado to hit Wales
Three people were killed, houses and a chapel were wrecked and over 100 people injured when a force 6 Tornado struck Edwardsville, near Merthyr Tydfil, on 27 October 1913.
“Men were lifted from their feet and dashed to the ground” according to a press report.
Roofs were lifted several miles. A hayrick weighing several tons was carried for a mile. Near Pontypridd half a ton of brick chimney was carried several hundred yards. It was associated with a thunderstorm that was seven miles wide, although the tornado was only about a hundred yards wide.
Damage to property was estimated at £40,000 which is equivalent to around £2.5 million today.
The tornado was accompanied by intense lightning and torrential rain as it reached its peak at Abercynon and Edwardsville.
An investigation in the aftermath of the storm and concluded that the tornado contained winds blowing in an anti-clockwise direction.
“The width in South Wales was three hundred yards; the maximum duration of the storm at any one place must have been about seventeen seconds.”
The wind speed was not recorded, as no weather stations in the area had the correct recording equipment. However, changes in air pressure were recorded in several places.
They revealed a sudden drop in pressure followed by an almost immediate rise.
The Met office investigators stated: “This fall of 0.3 inch, or 1/100 of the normal atmospheric pressure of 15lbs to the square inch, means a sudden change in the atmospheric pressure of O.15 lb per square inch, or about 20 lbs per square foot.
“Such a change of pressure, if applied suddenly to the outside of a closed building, must produce an effect similar to an explosion within, and it is thus easy to understand how windows or even whole walls are blown outwards, as at the generating station at Treforest”.
The Met Office investigation concluded with these points: “(It was) a genuine tornado of the type common enough in parts of America. The violent electrical phenomena, the heavy rainfall, the roaring noise, the sudden decrease of barometric pressure, resulting in the blowing out of walls of buildings, as if by explosion from within, are all features which are common in descriptions of American tornadoes.”