A severe storm is one that results in unusual weather that differs from the common weather types. Severe storms may cause a lot of damage and can even result in a loss of lives. There are various kinds of severe storms, but some of the main ones include thunderstorms and lightning, hurricanes, and tornadoes. These extreme weather events happen all over the world and may be very dangerous to the people involved.
Thunderstorms and Lightning
Thunderstorms happen when it is raining, and thunder can be heard. This thunder comes from what is called lightning. During a thunderstorm, thunder and lightning will occur, along with the possibility of hail, tornadoes, and extreme wind gusts. When wind gusts are faster than 57.5 MPH, the storm is considered to be a severe thunderstorm. Thunderstorms are a result of low air pressure.
Life Cycle of a Thunderstorm
There are three stages in the life cycle of a thunderstorm. Before a thunderstorm begins, cumulus clouds are present, which may turn into cumulonimbus clouds during the storm. These stages include the cumulus stage, mature stage, and dissipating stage (National Severe Storms Laboratory-a). The Cumulus stage includes a cloud beginning to form because of an updraft. The updraft then starts to cool and condense. During this first stage, small raindrops form but push up into the cloud by the flow of the wind from the updraft.
Once these smaller raindrops form together and become big enough to fall to the ground, it becomes the second stage, called the Mature stage. During this stage is when the heaviest amount of rain, and possibly hail, occur. Along with the rain, cool air comes, which is called a downdraft. Eventually the downdraft stops the updraft, which leads to the last stage. During the Dissipating stage, the updraft is fading out, which kills the thunderstorms because the updraft is what feeds the thunderstorm. All that is left after the thunderstorm ends are wispy-looking clouds.
Types of Thunderstorms
There are nine different types of thunderstorms. These storms include single-cell thunderstorms, multi-cell storm, squall line, supercell, “Bow echo”, Mesoscale Convective System (MCS), Mesoscale Convective Complex (MCC), Mesoscale Convective Vortex (MCV), and Derecho (National Severe Storms Laboratory-a).
There are various things that go into determining what kind of thunderstorm may take place. The speed of the wind determines the type of thunderstorm that occurs. A wind shear, which changes the speed and direction of a storm, also determines the type of thunderstorms that will happen (Haby & Sincavage, 2018).
In “Lightning Basics” authors state, “lightning is a giant spark of electricity in the atmosphere between clouds, the air, or the ground” (National Severe Storms Laboratory-b). There are various types of lightning, but the two main types are cloud to ground lightning and cloud to air lightning (National Severe Storms Laboratory-b). Scientists are not exactly sure on how lightning is formed, but there are two different theories as to how this happens. Precipitation theorists believe that the various sizes of raindrops and hail collide, causing their negative particles to fall to the bottom of the cloud which causes the lightning (National Severe Storms Laboratory-b). On the other hand, convection theorists think that the updrafts bring the positive charges up and the downdrafts bring the negative charges down (National Severe Storms Laboratory-b).
It is possible to see lightning and not be able to hear the thunder because the distance is too great between the storm and location one may be in. There is a saying “If you hear thunder, lightning is close by.” This simply means that since lightning causes thunder, if you hear thunder, there must be lightning near. Lightning causes air to expand rapidly which creates the sound that is known as thunder. It is possible to estimate how far away thunder is. This can be done by counting each second from the time you see lightning until you hear the thunder. For every five seconds counted, the lightning is one mile away (Kids’ Crossing).
Dangers of Lightning
On average, 2000 people are killed every year from lightning. Many people survive lightning strikes, but have symptoms as a result from the strike, including memory loss, severe burns, and cardiac arrest. Houses may seem safe from lightning, but when a person is inside and touches water, they run the risk of being shocked. Lightning is dangerous because it is difficult to determine where it will strike (National Geographic, 2009).
Safety Procedures for Thunder and Lightning
Right after hearing thunder, one should go indoors or find shelter because it is likely they are in close enough proximity to the storm that they could be struck. If getting indoors is not an option, staying away from open fields and water is the safest (National Weather Service). If getting indoors is possible, one should stay in a place with electricity, stay away from phones that have cords, and stay away from plumbing, such as washing hands. Thunderstorms are considered sever weather because they can cause a lot of damage. This damage includes flooding, fires from lightning, damage to property from hail, and strong winds that can knock trees down. It is very important to find safety when this occurs.
More Helpful Source
I found the book to be more helpful than the information posted at the website listed while helping to increase my understanding of lightning. I did not realize that one could be shocked through the water while inside of a house. I always have used the plumbing without any hesitation or thought during a thunderstorm.
Hurricanes are storms that form over warmer bodies of water with winds that reach 74 MPH and occur in the Atlantic and Northeast Pacific. In the Northwest Pacific, hurricanes are called typhoons. In the South Pacific and Indian ocean, these storms are considered to be cyclone. They are all tropical storms that reach wind speeds of 74 MPH or more but are named based on the location (African Reporter, 2017).
Formation of Hurricanes
Hurricanes from in tropical waters with a warm and moist atmosphere. They usually form from the warm air rising away from the surface of the ocean, which leads to lower pressure air under this. Following this, the higher-pressure air from other areas go into this area with the lower pressure air. This new air rises, and the process continues. All of this moist air creates clouds that spin, which is fueled by the warm water evaporating from the surface of the water (NASA Space Place, 2018).
In order for a hurricane to form, there must be certain conditions present. These conditions include warm, deep water. This water must be a minimum of 80 degrees Fahrenheit and no less than 200 feet deep. There must also be a light wind shear because wind shears stop the formation of hurricanes. Finally, warm and moist air must be present (E-Missions).
In 2017, it was predicted that there would be five to nine hurricanes in the Atlantic Ocean during the 2017 hurricane season. At the end of the 2017 hurricane season, there were a total of 10 hurricanes in the Atlantic Ocean (National Oceanic and Atmospheric Administration, 2017). The hurricane season had a lot of activity in terms of storms. As a result of this, it cost the United States $202 billion, but $370 billion worldwide (Uria, 2017). The 2005 hurricane season holds the record for the highest number of hurricanes during one season, with a total of 15. However, in the past ten years, 2010 holds the highest number of hurricanes, with a total of 12. This is ranked second, after 2005 (Weather Underground). The NOAA claims that the hurricane season in the Atlantic Ocean is from June 1st until November 30th.
A tropical depression is a combination of thunderstorms and low-pressure air producing a maximum wind speed of 39 MPH. A tropical storm more intense than a tropical depression, with winds father than 39 MPH, but the winds are slower than 73 MPH. Tropical storms have more organized wind patterns. Hurricanes are even more intense than tropical storms, with winds faster than 74 MPH (NASA). Strength of hurricanes is measured by using a scale called “Saffir-Simpson Hurricane scale.” This scale considers wind pressure, speed, and potential damage. From this, it is then ranked into five different categories. Category one is being minimal and category 5 is catastrophic (ESchool Today). As the wind speed increases, the strength of the hurricane increases.
El Niño and La Niña affect hurricane activity. El Niño strengthens the hurricane activity in the central and eastern Pacific but decrease the activity in the Atlantic. La Niña strengthens the hurricane activity in the Atlantic but decreases the activity in the central and eastern Pacific (National Oceanic and Atmospheric Administration, 2014). Being in the eyewall of the hurricane is the most dangerous and causes the highest amount of damage and loss of life. The location of the various parts of the hurricane can be tracked. The media uses a cone shaped track path to show hurricanes. They show this shape because the cone shows predicted paths for the hurricane, but the path may vary from what is predicted (National Hurricane Center).
Naming of Hurricanes
In the Atlantic, there is a six-year rotation of male and female names for the naming of hurricanes. This list would only change if the storm is very damaging. Names of hurricanes are not repeated if the hurricane is very intense or damaging. This is out of respect to those that suffered losses due to these storms. Some hurricane names that are no longer in rotation include Harvey, Irma, and Maria (National Oceanic and Atmospheric Administration, 2018-b).
When in the path of a hurricane, it is very important to take various safety precautions to survive. These safety precautions include putting together an emergency kit. This kit should have things such as flashlights and generators. Having an emergency plan in place with friends and family will help to make sure everyone stays safe. Strengthening the area around homes will help to decrease the damage caused by the storm, along with provide a better and safer place to take shelter in. Before the hurricane arrives, everyone should be aware of how to get information about hurricanes from various sources, so they can stay updated on the storm (National Oceanic and Atmospheric Administration, 2018-a).
According to “Tornado Basics” a, “tornado is a narrow, violently rotating column of air that extends from the base of a thunderstorm to the ground” (National Severe Storms Laboratory- c). Tornadoes form from a type of thunderstorm, called a supercell. Scientists are unsure if this weather is related to temperature differences or not. For a tornado to form, there must be certain conditions present. These conditions include violent thunderstorms with instability and wind shear in the lower atmosphere. The instability refers to warm and humid conditions in the lower atmosphere with cooler air in the higher atmosphere (Weather Questions).
Strength of Tornadoes
Strength of tornadoes is measured by looking at damage caused by the tornado, using the F-scale, or using the EF-scale. The EF-scale considers other factors, rather than just the damage from the storm. From these scales, there are different classifications that tornadoes are categorized. These classifications include light, moderate, considerable, severe, devastating, and incredible damage. For the EF-scale, light damage has winds 65-85 MPH, moderate 86-110 MPH, considerable 111-135 MPH, severe 136-165 MPH, devastating 166-200 MPH, and incredible damage is over 200 MPH. Those numbers differ for the F-scale. For light damage, the winds are 40-72 MPH, moderate 73-112 MPH, considerable 113-157 MPH, severe 158-207 MPH, devastating 208-260 MPH, and incredible damage 261-318 MPH (Old Farmers Almanac). Most of the tornadoes fall into the category of moderate damage.
Microbursts and Waterspouts
A microburst is a downward burst of air at the bottom of a thunderstorm. This differs from a tornado because of its path, but it can have the same damage. A microburst makes a starburst pattern with straight winds, while a tornado makes a swirled pattern. On the other hand, a waterspout is a type of non-supercell tornado. It happens when thunderstorm clouds are still growing without a rotating updraft that occurs over water. A waterspout is a tornado that forms over water (National Severe Storms Laboratory-c). Both waterspouts and microbursts are produced or related to severe thunderstorms.
General Tornado Information
Tornadoes usually occur in spring and summer. Most of the storm cells containing tornadoes travel in a west to east pattern. Tornadoes are generally uncommon in mountainous areas. This is because the air in mountainous areas tends to be more stable, meaning that it has cooler air that does not have frequent changes. This type of environment is not where tornadoes favor, but it is still possible for them to happen in these mountainous areas (Means, 2017).
Tornadoes spawn from hurricanes because hurricanes have the perfect conditions for tornadoes. This includes the instable atmosphere, wind shear, and usually carry supercells. Supercells are thunderstorms that can produce a tornado. Signs of an approaching tornado include a dark green sky, wall clouds, large hail, still air, a cloud of debris, and a loud roar (Emergency Medical Services Authority).
Tornado Watch versus Tornado Warning
A tornado watch is issued when a tornado may come through an area within the next few hours. When this happens, it is necessary to prepare to find shelter in case the warning is issued later, or if the tornado comes through. On the other hand, a tornado warning is issued when a tornado is spotted. When this happens, it is necessary to find shelter immediately (National Severe Storms Laboratory-c).
Lasting Effects of Tornadoes
When a tornado strikes, it is possible for lives to be lost, homes damaged, roads damaged, and power and phone lines ruined. There is also a loss of money and decrease in economic activity due to less tourist visits and a decrease in productivity and sales. However, following a tornado and the initial economic decrease, it is seen that there is an increase in economic activity due to the improvements needed to be done to fix the damage (Johnston).
It may be thought that a state that has the highest number of tornadoes means that it would have the most injuries and deaths. This is not the case. Not many people are killed each year by tornadoes. While tornadoes may be dangerous, they may not always be deadly. There are other factors that lead in to the total number of injuries and deaths, such as diseases and other natural disasters. The last tornado that killed someone was on September 5, 2018. This happened in the state of Virginia (Storm Prediction Center).
DIY Tornado Model
One way to replicate the movement of a tornado is to make one in a bottle. Filling this bottle with water and adding dish soap and a pinch of salt will make this happen. After shaking the bottle in a circle, it creates what looks to be like a vortex. The water continues to spin around this vortex. A tornado is a vortex.
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