Last week we told you about a powerful hail storm in South Dakota the could wind up being a record breaker. Today, it became official. A hail stone recovered in Vivian, South Dakota measured 8” in diameter and and weight just under 2lbs. Those figures break both records in the US previously held by separate events in Kansas and Nebraska. The hail stone fell in South Dakota back on July 23rd during a severe thunderstorm. Not something you’d want flying towards you.
Taking a look at some of the technical data released by the National Weather Service. To give you an idea of the power of this hail producing supercell, forecasters estimate the updrafts in the hail storm were as strong as 180mph.
Turning to the radar during this storm, the radar scan to the right really tells the tale. You can see some just off the chart reflectivity returns over the affected area. Notice the area of light rain to the southwest that I’ve circled? That’s not rain, that’s called Third Party Scatter. It is produced when large hail forms, and the radar image is reflected a few times by the stones before returning to the radar site. That gives the radar the misperception that the beams traveled further and gives the indication of light rain further beyond the radar site than the supercell.
Although this is all really cool to look at now, it certainly is not cool for those caught in the path of it. You want to see how much power hail stones like this can have? Look at the pictures below. They show the wooden deck this stone smashed through and the divot it left behind.