Hail & Excessive Heat - Severe Weather Awareness Week
Friday, April 12th, 2024 -- 6:01 AM
(Part 5 of a 5 part series)
We wrap up our look at Severe Weather Awareness Week with two more deadly hazards.
The first hazard is hail. Hail is a form of precipitation consisting of solid ice that forms inside thunderstorm updrafts. Hail can damage aircraft, homes and cars, and can be deadly to livestock and people. Hailstones are formed when raindrops are carried upward by thunderstorm updrafts into extremely cold areas of the atmosphere and freeze. Hailstones then grow by colliding with liquid water drops that freeze onto the hailstone’s surface. Hail falls to the ground when it becomes heavy enough to overcome the strength of the thunderstorm updraft and is pulled toward the earth by gravity. Smaller hailstones can be blown away from the updraft by horizontal winds, so larger hail typically falls closer to the updraft than smaller hail. If the winds near the surface are strong enough, hail can fall at an angle or even nearly sideways! Wind-driven hail can tear up siding on houses, break windows and blow into houses, break side windows on cars, and cause severe injury and/or death to people and animals. 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 definite size are good, but measurements using a ruler, a caliper, or a tape measure are best.
- 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
- Tea cup = 3 inches
- Softball = 4 inches
- Grapefruit = 4 1/2 inches
The second summer hazard is the heat. Summer heat waves have been the biggest weather-related killers in Wisconsin for more than 50 years, far exceeding tornado and other storm-related deaths. Thousands of Wisconsinites fall ill or are hospitalized for heat-related illnesses each year. The inside of a vehicle can be especially dangerous. On an 80-degree Fahrenheit day, temperatures inside a vehicle parked in direct sunlight can climb almost 20 degrees in 10 minutes. Never leave people or pets inside a parked vehicle. Leaving a window cracked is not enough!
A Heat Advisory is issued within 12 hours of the start of a period of extremely dangerous heat conditions. The National Weather Service will issue a heat advisory when the daytime heat index values are 100 to 104. A heat advisory will also be issued if heat indices are 95 to 99 for four consecutive days.
A Heat Watch is issued when conditions are favorable for excessive heat in the next 24 -72 hours. An Excessive Heat Warning is issued within 12 hours of the onset of extremely dangerous heat conditions. This will be issued by the National Weather Service when the daytime heat index is 105 or higher during the day and 75 or higher at night for at least a 48-hour period. If heat indices are 100 to 104 for four consecutive days, an excessive heat warning will be issued.
This week we have taken a look at all the summer severe weather hazards. Knowlege of the hazards and being prepared for all of them will not only save your life but can help protect your personal property as well.
Feel free to contact us with questions and/or comments.