A thunderstorm can cause havoc in different ways. Today, I want to discuss hail.
Hail is a form of precipitation consisting of solid ice that forms inside thunderstorm updrafts. Hail can damage aircraft, homes and vehicles, and can be deadly to livestock and people. Another important aspect of hail in South Dakota is its ability to damage our crops.
Hail is not only dangerous to your vehicle’s windshield, but can be dangerous to humans and animals caught outdoors as well. If you are outdoors, head indoors and stay away from windows or skylights. Similarly, if you are in a vehicle, use a coat or spare clothing to shield yourself from any potential of windows or windshields breaking. Stopping under an overpass to protect your vehicle is not a safe shelter and may impede traffic flow for any additional weather hazards that may be present.
How large can hail get? The largest hailstone recovered in the U.S. fell in Vivian, South Dakota, on June 23, 2010, with a diameter of 8 inches and a circumference of 18.62 inches. It weighed 1 lb. 15 oz.
According to the Brookings County Pre-Disaster Mitigation Plan, the largest hail stone reported was 3 inches and it was collected in Volga on June 18, 2012. There is a note in the plan that larger hail stones probably fell in the past, but no one measured them.
How do you estimate/measure hail size? To start with, one thing that I have heard countless times about measuring hail size is that you never report it as being marble-sized. Why, you may ask. Look into how many sizes of marbles there are in the world, and you will find out quickly that your marble is probably different than my marble. The same thought process applies to taking a photograph while holding it in your hand — how large is your hand?
Hail size is often estimated by comparing it to a known object. Most hailstorms are made up of a mix of different sizes, and only the very largest hail stones pose serious risk to people caught in the open. When reporting hail, estimates comparing the hail to a known object with a definite size are good, but measurements using a ruler, calipers, or a tape measure are best.
If you do not have a tape measure, you could use a dollar bill or follow these rough estimates. We will start smallest to largest:
• Pea = 1/4 inch diameter
• Mothball = 1/2 inch diameter
• Penny = 3/4 inch diameter
• Nickel = 7/8 inch
• Quarter = 1 inch — hail quarter size or larger is considered severe
• Ping-pong ball = 1 1/2 inch
• Golf ball = 1 3/4 inches
• Tennis ball = 2 1/2 inches
• Baseball = 2 3/4 inches
• Teacup = 3 inches
• Softball = 4 inches
• Grapefruit = 4 1/2 inches.
I always tell people that if you get a hailstone the size of a basketball to call me; I really would like to see it.
Historically, Brookings County in the past has experienced the following incidents that mentioned hail specifically:
July 31, 1909: Crops were completely destroyed by hail for a distance of 4 to 5 miles north of the city of Brookings, but none fell in the city itself. This storm did not “leave a straw standing after it passed.” Farms were hit north and west of Bruce, east of Brookings, east of Elkton, and it hailed for 30 minutes in Aurora.
July 18, 1963: Winds were clocked at 100 miles per hour and hail the size of baseballs was reported along an area 8 to 10 miles wide reaching from northwest to southeast of White, with the city receiving damage by having bricks torn off a building. Differing reports gave credit to a small twister, lightning, or high winds “sucking” the bricks off the wall. Cows caught in the storm received 2- to 3-inch bruises from falling hailstones.
June 2001: Large hail falling over an area 20 miles long and almost 5 miles wide caused property and crop damage. The hail damaged siding and windows of homes as well as vehicles. An estimated 60,000 acres of crops were destroyed or damaged. Hail was discovered piled up 6 inches deep in some fields six hours after the storm. The affected area included the city of Brookings, where some of the largest hail was reported. Damages were estimated at $2 million in property damage and $4 million in crop damage.
April 2004: Large hail accompanied by winds gusting to 50 mph dented vehicles, cracked and broke windshields and windows, dented siding, and damaged roofs. Property damage was estimated at $500,000.
If it is storming outside, you may want to avoid glass windows, as larger hailstones can break glass easily along with other debris that a violent thunderstorm can produce.
Today’s information was provided by the National Weather Service/NOAA.
Remember, keep an eye on the sky.
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