Wednesday, July 24, 2013

How does it compare?

8" monster in Vivian, SD (2010)

7.75" hail stone in southwest Wichita (2010)

4.75" hail last night in Yoder

Tuesday night's storms will be talked about for some time! The bottom picture shows the hailstone that fell in Yoder last night.  It was 4.75 inches in diameter, slightly larger than softball size.  In Hutchinson, the largest hail reported was grapefruit size or 4 inches in diameter.  But how does that stack up to past storms?

In July 2010, a monster hail stone in Vivian, South Dakota measured 8 inches in diameter, the largest ever recorded! (top picture) Two months later (middle picture), a massive hailstone fell in southwest Wichita.  It was 7.75 inches in diameter, making it the largest hailstone ever for the state of Kansas, surpassing the Coffeyville hailstone from 1970. (5.7" in diameter)

Yes, 4.75" hail is extremely large hail but compared to the 2010 storms in Vivian and Wichita, it doesn't come close...thankfully.  

But how does hail get that big?  Hail forms and then grows as a thunderstorm updraft carries raindrops in an up and down cycle through below freezing and above freezing layers inside the storm.  A less intense updraft will allow fewer trips through the growth cycle so it falls to the ground before getting too big.  Crank up the speed though and that hailstone spends a longer period of time within the storm and gets much larger before falling to the ground.Within the storm's updraft, wind speeds of around 65 mph are needed to support the formation of golf ball size hailstone.  If updraft speeds reach 80 mph,  tennis ball size hail can form and with 100 mph or greater, softball size hail or larger can form.  In the case of the Vivian 8" hail stone, the updraft was estimated at 160 to 180 miles per hour!

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