Tornado
A tornado is a violent rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes are capable of tremendous destruction with wind speeds of up to 300 mph. They can destroy large buildings, uproot trees and hurl vehicles hundreds of yards. They can also drive straw into trees. Damage paths can be in excess of one mile wide to 50 miles long. In an average year, 1000 tornadoes are reported nationwide.
How does Tornado form?
Most tornadoes form from thunderstorms. When warm, moist air and cool, dry air masses meet, they create instability in the atmosphere. A change in wind direction and an increase in wind speed with increasing height creates an invisible, horizontal spinning effect in the lower atmosphere. Rising air within the updraft tilts the rotating air from horizontal to vertical. An area of rotation, 2-6 miles wide, now extends through much of the storm. Most strong and violent tornadoes form within this area of strong rotation.
Several conditions are required for the development of tornadoes and the thunderstorm clouds with which most tornadoes are associated. Abundant low level moisture is necessary to contribute to the development of a thunderstorm, and a “trigger” (perhaps a cold front or other low level zone of converging winds) is needed to lift the moist air aloft. Once the air begins to rise and becomes saturated, it will continue rising to great heights to produce a thunderstorm cloud, if the atmosphere is unstable. An unstable atmosphere is one where the temperature decreases rapidly with height. Atmospheric instability can also occur when dry air overlays moist air near the earth’s surface. Finally, tornadoes usually form in areas where winds at all levels of the atmosphere are not only strong, but also turn with height in a clockwise or veering direction.
Related Post: Powerful Weather Forces: Hurricanes, Cyclones and Typhoons
Tornadoes can appear as a traditional funnel shape, or in a slender rope-like form. Even others may be nearly invisible, with only swirling dust or debris at ground levels as the only indication of the tornado’s presence. It is not fully understood about how exactly tornadoes die. Tornado researchers are still trying to solve the tornado puzzle.
Tsunami
A tsunami is a series of ocean waves that sends surges of water, sometimes reaching heights of over 100 feet (30.5 meters), onto land. These walls of water can cause widespread destruction when they crash ashore. Tsunamis are ocean waves produced by earthquakes or underwater landslides. As the waves approach the coast, their speed decreases and their height increases. Waves that are 10 to 20 feet high can be very destructive. Tsunamis don’t happen very often, but when they do they cause many deaths and injuries. In deep ocean, tsunami waves may appear only a foot or so high. But as they approach shoreline and enter shallower water they slow down and begin to grow in energy and height. The tops of the waves move faster than their bottoms do, which causes them to rise precipitously (in a very quick and sudden way).
When the ocean floor at a plate boundary rises or falls suddenly it displaces the water above it and launches the rolling waves that will become a tsunami.
Tsunamis may also be caused by underwater landslides or volcanic eruptions. They may even be launched, as they frequently were in Earth’s ancient past, by the impact of a large meteorite plunging into an ocean.
You can make a tiny model of a tsunami by dropping a rock into a bowl of water, causing ripples to propagate (travel) outwards from the site of impact. Another way is to slightly jolt the bowl of water and watch it slosh over the rim on one side, that’s exactly what a tsunami looks like.
Reference: National Geographic and WeatherWizkids
