Tornados

1. Tornados • Most destructive by product of a thunderstorm • Violently rotating column of air that usually touches the ground • Produces the fasted winds on Earth • Can cause severe property damage, personal injury, and loss of life • Measured on the Fujits Tornado Intensity scale • Lowest F0 (65 km/hr or 40 mph)- windows broken • F5 (513 km/hr or 318 mph) Lifts and moves buildings • Safety: stay or go indoors into the basement, avoid large spaces and windows, cover with mattress/ furniture • If outdoors, lie down, avoid vehicles, and cover your head and neck

2. Tornados • Caused by the collision of warm moist air and cold dry air • This causes a supercell (very large thunderstorm system) that contains a strong, rotating updraft • Formed from dark gray storm clouds that lower down to the ground • This forms a funnel shape • Tornadoes can strike anywhere throughout the U.S. but most often appear in the Midwest • More likely to occur when there are large temperature differences in high and low altitude air in the spring

3. Hurricane • A large rotating storm from the tropics with sustained winds of at least 74 mph • Very low pressure at the center, or the eye, which is very calm • Right outside the eye, in the eye wall, are the strongest winds and heaviest rains • Must have a supply of warm moist air for a long period of time to form • The humid air begins to rise. As it rises, it cools and conenses which gives off heat • Humid air flows in at the bottom to replace the rising air • This causes the air to cycle, and then eventually spin

4. Hurricane • Hurricanes begin to lose strength once they’re over land because there is no more moist air to fuel the storm • It has heavy winds, destructive waves, and flooding that can damage property, cause injury, and death To prepare for a hurricane: • Gather emergency supplies • Radio, flashlight, food and water • Shut off water and electricity • Evacuate home to designed areas calmly

5. Monsoon • A monsoon are winds that change seasonally that usually bring heavy rainfall, high winds, and thunderstorms • They are caused by the change of season, which causes changes in global air pressure • In Arizona, this causes the prevailing winds to change and come from the southwest • Rain is no longer hits the mountains in California, and makes its way to Arizona instead • Monsoon season in Arizona is between June 15 to September 30

6. Monsoon • Monsoons often are associated with dust storms and thunderstorms • This can be dangerous to drivers and home owners • They can cause lightning strikes, flash floods, impair visibility, and cause high enough winds to tear down trees • To be safe during a monsoon: • Don’t drive through areas filled with water • Turn off unnecessary electronics • If you are driving during a monsoon, pull off to the side of the road, turn off your car and lights, and turn off your vehicle

7. Floods • An overflowing of water onto land that is normally dry • Caused by heavy or long lasting rains, or rapid melting of winter snows • Can also be caused by failing dams and a lack of trees and vegetation • Flash floods are rapid flooding of low-lying areas like washes rivers and streams • Floods can damage property, spread disease and bacteria, and cause the loss of human and animal life

8. Floods • Floods can also add sediments and nutrients back to the land to enrich the soil • Can be an important annual event to water and grow crops • To prevent floods, levees (man made embankments built to keep rivers from overflowing) can be built • Vegetation can be planted, as plant roots slow down runoff and erosion

9. Drought • A drought is a period in which rainfall is below the expected average for that location • Climate is so dry for an extended period that native plants can’t grow • Droughts can adversely affect both water and food supplies • Droughts are worse in poor countries that depend on rainfall to grow crops because they have no irrigation • Can be worsened by poor land management

10. Drought • Droughts can reduce the runoff of pollution into waterways • This can improve the quality of water in lakes, rivers, and bays • Droughts can cause desertification: the near permanent process that turn fertile land into infertile desert • Can help be prevented by soil and water conservation • Improved animal herding techniques • Better and increased storage of water in aquifers

11. Thunderstorms • Characterized by towering cumulonimbus clouds, torrential rain, hail, thunder, and lightning • Usually occur in mid afternoon heat because of warm, moist, unstable air • Cold front causes this warm air to rise rapidly in convection cells • A single cell of thunderstorms can last for an hour, while multiple cells can last for a day or more

12. Thunderstorms • Thunderstorms are associated with lighting, which is a discharge of electricity from a thundercloud to the ground, or from cloud to cloud • Lightning can cause damage to people and structures, set fires • Attracted to tall objects, as well as metal objects • If caught in a thunderstorm • Stay away from water, trees, high ground, and metal • Remain 15 ft from other people, and get low • If indoors, stay away from the phone, plumbing, electrical appliances, doors, and windows