Severe weather is generated by the changes in the atmosphere’s temperature, wind or air pressure. Some examples of these extreme weather events include thunderstorms, damaging winds, tornadoes, hail storms, flooding, drought and winter storms.. All of these can be exceptionally dangerous and cause a lot of damage.
A thunderstorm is a rain shower that includes thunder and lightning. A thunderstorm becomes severe when it contains one of the following: hail one inch or greater, wind gusts exceeding 50 knots or 57.5 miles per hour, or a tornado. It is estimated that over sixteen million thunderstorms occur worldwide each year. In the United States, thunderstorms occur mostly in the spring and summertime. There are about 100,000 thunderstorms each year; only10% of those thunderstorms, however, are considered extreme weather and reach severe levels. In the United States, Florida has reported having the most thunderstorms; while the states that have reported the most severe thunderstorms are Iowa, Texas and Louisiana.
Damaging winds, also known as straight- line winds, are classified when they exceed 50-60 miles per hour. This occurs as a result of a thunderstorm’s downdraft. It is common for these severe winds to cause more damage than a tornado. The faster the wind speeds are, the more damage can occur, extending to hundreds of miles. People most at risk for injury or death from a damaging wind storm are those who live in mobile homes.
A tornado is a narrow, violently rotating column of air that extends from a thunderstorm to the ground. Tornados are one of the most violent phenomena of all storms that humans experience. They take place all over the world, and affect the United States specifically 1,200 times a year. Although tornadoes can take place any time of year, they are regularly seen in the southern plains (Texas, Oklahoma and Kansas) in May and June and in the northern plains and upper Midwest (North and South Dakota, Nebraska, Iowa, and Minnesota) in June and July.
Hail is a type of precipitation consisting of solid ice that forms inside thunderstorm updrafts. Hailstorms are formed when raindrops are carried upward from thunderstorm updrafts into extremely cold areas of the atmosphere and freeze. Hail falls to the ground when it becomes heavy enough to survive the strength of the thunderstorm updraft and is pulled toward the Earth by gravity. Hail can fall at different speeds and be different sizes.
For students to really understand the different sizes of hail I have included some examples to help them visualize the different diameters:
For small hailstorms, less than 1 inch in diameter, the fall speed is between 9-25 miles per hour. For reference, the hail can look as small as a pea or as large as a nickel. Hailstorms that take place during a thunderstorm can be 1 to 1.75 inches in diameter and fall at a speed between 35-40 miles per hour. For reference, the hail can be as small as a quarter or as large as a golf ball. In the strongest and largest hail storm, it was reported that the hail was 2 to 4 inches in diameter and expected fall speed to be 44 to 72 miles per hour. For reference, the hail can look as small as a tennis ball or as large as a softball.
Although Florida has the most thunderstorms, Nebraska, Colorado and Wyoming are known to have the most hailstorms. They have an average of nine hail days per year. The most damaging hail storms have occurred in China, Russia, India and Northern Italy. The largest hailstorm in the United States took place in Vivian, South Dakota on June 23, 2010. The hail had a diameter to 8 inches and weighed 1 pound and 15 ounces. Hail can cause a lot of damage to homes and cars and can be deadly to people and animals.
Flooding is an overflowing of water onto land that is normally dry. Flooding can occur during heavy rain storms, when snow melts quickly or even when dams break. The number of floods can transpire within minutes or over a long period of time. They can last hours, days or even weeks depending on the severity of the flood. Floods are the most common of all weather related natural disasters. Floods occur in every state and territory here in America. The most dangerous kinds of floods are called flash floods. Flash floods take place when heavy rainfall exceeds the ability of the ground to absorb it. This causes a rapid rise of water in a short amount of time. Areas that are at the most risk from flash floods are densely populated areas or areas near rivers or dams. It is reported that in the United States, floods kill more people each year than tornadoes, hurricanes or lightning.
A drought is a period of time when an area or region experiences below normal precipitation. The lack of rain or snow can reduce groundwater, minimize stream flow, damage crops and cause water shortage. Although it is hard to predict when a drought begins and when it ends, it can last weeks, months or even years. The longer a drought lasts, the more harm it will cause for people. This is because clean drinking water is crucial for all living things. Crops need clean water to grow with the help of irrigation. Irrigation is only possible when there is enough water in surrounding rivers, lakes, streams or groundwater. During a drought, these sources of water can be lessened or even dried up completely. In turn, this can prevent crops from being irrigated and result in them dying. In the United States, the states that face the most droughts are California, Nevada, Utah and Arizona. Droughts are the second most costly weather events after hurricanes. This is resulting in more frequent and severe droughts in these regions of the United States (Bates, 2021).
A winter storm is a combination of heavy snow, blowing snow and dangerous wind chills. Examples of winter storms are blizzards, ice storms and snow squalls. They can be very dangerous and life threatening depending on the severity of the storm. Blizzards are formed from blowing snow and winds with very low visibility. Blizzard winds can reach average speeds over 35 miles per hour. Visibility can be reduced to a quarter mile or less for at least three hours. An ice storm can cause at least .25 inches of ice to accumulate on an exposed surface. This creates very dangerous driving and walking conditions. In addition, the weight of the ice can also cause tree branches and powerlines to snap easily. Snow squalls are intense, brief snow showers combined with strong winds. They cause sudden white out conditions combined with falling temperatures that produce icy roads in just minutes. They take place quickly and last less than an hour, but can cause a lot of damage due to the lack of visibility while driving.