nathural deaasater

1. Tornadoes are violent storms that strike as a powerful rotating mixture of wind and thunderstorm clouds, extending from the clouds to the ground in a funnel shape. They are know to be the most powerful and destructive atmospheric generated phenomena and are very common in the USA, particularly from the middle belt extending to the east coast.

2. Every year, there is an average of 800 tornadoes that hit various parts of the USA. Even though many of them are very mild and could be seen as just strong winds, there has been a few tornadoes that have been very devastating and flattened many homes, schools and structures along its path. Tornado incidents are distributed all year through, forming particularly in late spring (March), with the most incidents occurring in the summer (May and June), and reducing in numbers and strengths in the fall.

3. Tornadoes occur usually during daytime, from mid- afternoon till about early evening. Their movement is usually from the southwest to the northeast. Sometimes they move in any direction, and in the general path of the thunderstorm. The spinning winds cover an area of about 300 400 yards, and can travel on a path for about 5 miles (some tornadoes travel for over 80 miles), at a speed of about 5 60mph. Sometimes tornadoes develop in a very short time frame, leaving very little lead time for warning and preparation.

4. This question is one that has not been a bit uncertain among people who study weather, but here is an explanation that many believe is the closest possible cause of tornadoes.

5. Step 1: Like all winds and storms, tornadoes begin when the sun heats up the surface of the land. As the warm, less heavy air begins to rise, it meets the colder, heavier air above it. Note that wind shears make it even easier to set them off. A wind shear is when two winds at different levels and speeds above the ground blow together in a location. Step 2: The faster moving air begins to spin and roll over the slower wind. As it rolls on, it gathers pace and grow in size. step 3: At this stage, it is an invisible, horizontal wind spinning and rolling like a cylinder. As the winds continue to build up, stronger and more powerful warm air forces the spinning winds vertically upward, causing an updraft.

6. Step 4: With more warm air rising, the spinning air encounters more updraft. The winds spin faster, vertically upwards, and gains more momentum. Step 5: At this stage, the spinning winds, creates a vortex and the the wind has enough energy to fuel itself. Step 6: The tornado is fully formed now and moving in the direction of the thunderstorm winds. When the pointed part of the tornado touched the ground from the cloud, it is often referred to as 'touch down' As it moves it rips off things along its patch.

7. here are a few examples: April 25-28, 2011, USA: More than 200 tornadoes across Northern Mississippi, Central and Northern Alabama, Eastern Tennessee, Southwestern Virginia and Northern Georgia resulted in 316 deaths. 15 of the tornadoes measured 4-5 on the E-F Scale, with 8 of them traveling for more than 50 miles. In Alabama, there were more than 2000 more injuries, with property damage in excess of 4.2billiondollars. Tuesday, April 29, 2014, Mississippi, USA: On this day, a massive Tornado ripped through Townships in Arkansas and Mississippi killing at least 34 people. It also caused various degrees of injuries to 200 more people. Homes were flattened and trees and cars were flying around

8. Before a tornado: Sometimes tornadoes do not give weather readers much time to get people prepared to take cover. Here are a few things to do in preparation, especially if you live in a tornado prone area: Always be aware of the safer places (Refuge areas) you can go to in your home before a tornado visits. If there is no basement in your home, consider finding a safe place close enough to your home where you can quickly take shelter. Make sure there are signs on the walls showing where the closest safe area is. If there is enough time, grab a few first aid items and stock up on water and some emergency supplies, that can take you a few days if things get very bad.

9. During a tornado: During an approaching tornado, quickly move to your basement or designated area if you are in a public place. These days, schools, hospitals and many business building have safer places where can take shelter. After a tornado: Lots of injuries occur after tornadoes too. Be careful when getting out of your shelter as damaged objects and structures may fall. Wear safety garments when walking and working through debris, as there could be broken glasses, exposed nails and other dangerous chemicals. Do not touch power lines and objects in water puddles as there may be live electrical wires around.

10. The earth's mountains, plains, plateaus, soils, rocks, etc. as we see it today is believed to have gone through many phases, with about 80% of it being carved out by the action of volcanoes.

11. A volcano is simply a rapture (opening or vent) on the earth's surface (crust) through which molten magma (extremely hot mixture of gases, lava, ash and other burning substances) escape on to the earth's surface.

12. Why do volcanoes erupt? Let us start with what the earth is made of: The earth is made up of three layer parts. The outer crust is the layer on which we live. It is estimated to be about 1800 miles deep. Then there is the mantle; and then the core (inner and outer core)

13. The mantle is made up of molten material and gases. Molten materials are solids (like rock) that have turned into liquid because of extreme heat. The name for molten rock and other gases in the earths mantle is Magma. When ever extreme pressure builds in the mantle, along openings or cracks in weak spots in the earths crust an eruption is likely to happen next. During an eruption, molten materials soon to become lava and gush out through spaces in the crust to the surface. Molten rock is called magma when it is inside the crust but once it gets to the surface of the earth it is called lava.

14. Eruptions can be in the form of lava fragments shooting into the atmosphere and forming thick clouds of lava. Some also flow slowly (non-violent) from the vent, flooding the area around it. Very fine particles of ash may also be discharged high into the stratosphere and further carried away by wind action. Fresh lava is believed to be about 2,200F. It can be red hot as it shoots from the vent and turn into gray or black as it cools.. In other types, lava also comes in thick, pasty form. And this is called volcano

15. Types of volcano Shield volcano lava domes cinder cones composite volcanoes.

16. Shield Volcanoes This is very fluid lava, usually from multiple vents or fractures, spreading over very large areas. The fluid- like nature of the lava, it does not allow it to pile up like a cone. The result is usually an elevation with a shape like a warriors shield. Mount Kilauea and Maunaloa in Hawaii are good examples of shield volcanoes. They are usually found at constructive or tensional boundaries

17. They are produced from eruptions with less viscous lava. Because it is less viscous, they do not spread far and cool off sooner. This means they pile around the vent and the dome grows only because of the expansion of the vent area within. Lava Domes

18. Cinder Cones These are the most common in the study of volcanoes. When lava is ejected into the air above, the fragments and fine particles fall as cinders (ash) around the vent, forming a cone. The height of cinder cones usually depend on how long the eruption takes and how much lava comes out. The cone has a depression (crater) in the middle where the vent is. Cinder cones can rise as high as 1200ft. A good example of a cinder cone is the Paricutin Volcano in Mexico.

19. Composite Volcanoes These are usually awesome in nature, rising up to about 8000ft and they include Mount Cotopaxi in Ecuador and Mount Fuji in Japan. They are seen as massive mountains. They are formed by alternating layers of ash, rock, dust and lava, (pyroclastic) and hence the name composite. They have steep slopes with a peak.

20. Volcanic eruptions in the sea Though ocean floors are thousands of miles below the water surface, they also experience many volcanic activities.

21. In shallow waters, eruptions tend to involve cold water coming into contact with extremely hot lava from beneath that ocean floor. The steam escapes high above the water surface. If the eruptions occur deeper in the ocean, the weight and pressure of the water above it suppresses its expulsion and keeps it mild. This means the ocean floor is not necessarily affected in any way.

22. How does the inside of a volcano look like?

23. The effects of volcanic eruptions Eruptions occurring close to human settlements may spill and destroy lives and property. People often have to be evacuated. Example: Chaparrastique volcano in El Salvador started erupting on 29 Dec, 2013. Anyone living within 2 miles of the volcano is evacuated.

24. Landscapes and natural sceneries can be destroyed Ash and mud can mix with rain and melting snow, forming lahars. Lahars are mudflows flowing at very fast pace Volcanic gases The concentrations of different volcanic gases can vary considerably from one volcano to the next. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other principal volcanic gases include hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halocarbons, organic compounds, and volatile metal chlorides.

25. Landscapes and natural sceneries can be destroyed Ash and mud can mix with rain and melting snow, forming lahars. Lahars are mudflows flowing at very fast pace Volcanic gases The concentrations of different volcanic gases can vary considerably from one volcano to the next. Water vapor is typically the most abundant volcanic gas, followed by carbon dioxide and sulfur dioxide. Other principal volcanic gases include hydrogen sulfide, hydrogen chloride, and hydrogen fluoride. A large number of minor and trace gases are also found in volcanic emissions, for example hydrogen, carbon monoxide, halocarbons, organic compounds, and volatile metal chlorides.

26. What is an Earthquake? Simply, earthquakes are the rumblings, shaking or rolling of the earth's surface. It is usually what happens when two blocks of the earth suddenly slip past one another, or break apart from each other as a result of tension caused by prolonged energy build up. Earthquakes come in many forms. It can be felt as a shock under your feet, or may be very powerful and destructive enough to flatten an entire city. They can happen anywhere, land or sea.

27. What are the types of earthquakes? Earthquakes can come in three main forms, depending on the plate movements that occur beneath the earth's surface. They could occur on a Convergent Boundary, Divergent Boundary or a Transform Fault.

28. Convergent boundary: Here, one plate is forced over another plate during movement creating a thrust fault. Divergent boundary: Here, plates are forced apart each other, usually forming a Rift Zone. This kind is common in ocean floors where new floors are created. An example is the Mid Atlantic Ridge. Transform fault: Unlike divergent and convergent, the plates here slip by each other. This is also called Strike-Slip.

29. Introduction to Flooding 1. Many of us have this idea that floods (or flooding) is simply, too much water around your house. People think that can be fun. Wrong. Flooding is a lot more than that. Flooding is extremely dangerous and has the potential to wipe away an entire city, coastline or area, and cause extensive damage to life and property. It also has great erosive power and can be extremely destructive, even if it is a foot high.

30. What is a flood? It is a natural event or occurrence where a piece of land (or area) that is usually dry land, suddenly gets submerged under water. Some floods can occur suddenly and recede quickly. Others take days or even months to build and discharge. When floods happen in an area that people live, the water carries along objects like houses, bridges, cars, furniture and even people. It can wipe away farms, trees and many more heavy items.

31. Floods occur at irregular intervals and vary in size, duration and the affected area. It is important to note that water naturally flows from high areas to low lying areas. This means low-lying areas may flood quickly before it begins to get to higher ground. In this lesson, we shall see more about what causes flooding, the types of flooding, some effects of floods and what we can do before, during and after floods occur.

32. What causes flooding? Rains River overflow Strong winds in coastal areas Dam breaking Ice and snow-melts

33. Rains Each time there are more rains than the drainage system can take, there can be floods. Sometimes, there is heavy rain for a very short period that result in floods. River overflow Rivers can overflow their banks to cause flooding. Strong winds in coastal areas Sea water can be carried by massive winds and hurricanes onto dry coastal lands and cause flooding. Sometimes this is made worse if the winds carry rains themselves.

34. Dam breaking Dams are man-made blocks mounted to hold water flowing down from a highland. The power in the water is used to turn propellers to generate electricity. Sometimes, too much water held up in the dam can cause it to break and overflow the area. Excess water can also be intentionally released from the dam to prevent it from breaking and that can also cause floods. Ice and snow-melts In many cold regions, heavy snow over the winter usually stays un-melted for sometime. There are also mountains that have ice on top of them. Sometimes the ice suddenly melts when the temperature rises, resulting in massive movement of water into places that are usually dry. This is usually called a snowmelt flood

35. Types of floods Flash floods Rapid on-set floods Slow on-set floods

36. Flash floods This kind occurs within a very short time (2-6 hours, and sometimes within minutes) and is usually as a result of heavy rain, dam break or snow melt. Sometimes, intense rainfall from slow moving thunderstorms can cause it. Flash floods are the most destructive and can be fatal, as people are usually taken by surprise. There is usually no warning, no preparation and the impact can be very swift and devastating. Rapid on-set floods Similar to flash floods, this type takes slightly longer to develop and the flood can last for a day or two only. It is also very destructive, but does not usually surprise people like Flash floods. With rapid on-set floods, people can quickly put a few things right and escape before it gets very bad.

37. Slow on-set floods This kind is usually as a result of water bodies over flooding their banks. They tend to develop slowly and can last for days and weeks. They usually spread over many kilometers and occur more in flood plains (fields prone to floods in a low-lying areas). The effect of this kind of floods on people is more likely to be due to disease, malnutrition or snakebites.

38. Economic During floods (especially flash floods), roads, bridges, farms, houses and automobiles are destroyed. People become homeless. Additionally, the government deploys firemen, police and other emergency apparatuses to help the affected. All these come at a heavy cost to people and the government Environment The environment also suffers when floods happen. Chemicals and other hazardous substances end up in the water and eventually contaminate the water bodies that floods end up in. In 2011, a huge tsunami hit Japan, and sea water flooded a part of the coastline. The flooding caused massive leakage in nuclear plants and has since caused high radiation in that area.

39. People and animals Many people and animals have died in flash floods. Many more are injured and others made homeless. Water supply and electricity are disrupted and people struggle and suffer as a result. In addition to this, flooding brings a lot of diseases and infections including military fever, pneumonic plague, dermatopathia and dysentery. ...But... There is also something good about floods, especially those that occur in flood plains and farm fields. Floodwaters carry lots of nutrients that are deposited in the plains. Farmers love such soils, as they are perfect for cultivating some kinds of crops.