Hurricane and Tornad

Understanding Tornados

​
Sometimes really violent thunderstorms spawn tornadoes. A tor- nado is a narrow, rapidly spinning column of air extending downward from a cumulonimbus cloud. Condensing water vapor and debris lifted into the air by the low­pressure center usually creates a visible funnel. Hurricanes, tropical storms, and convective storms created by strong cold fronts can produce tornadoes. These devastating rotating storms occur over all continents except Antarctica, but they are most common and destructive in the southern and central sections of the United States—an area called Tornado Alley.

Tornadoes are associated with massive rotating storms called super- cells and form only under unusual circumstances. These supercell storms create a condition called wind shear, which is a large change in wind speeds at different altitudes. Wind shear creates a large horizontal rotating mass of air. The updraft within the thunderstorm tilts the mass of air vertically. The rotating air grows downward toward the ground, creating a funnel cloud. When the funnel extends downward and finally touches the ground, it is considered a tornado. Because tornadoes are relatively infrequent and destructive, meteorologists consider them separate windstorms from the storms that create them

At a distance, a tornado often looks like a gigantic elephant’s trunk or a thin rope dangling from a cloud. A very large one looks like a wide, black cylinder connecting ground and cloud. An average funnel is about 400 m in diameter at its base, the part in contact with the ground, but can range from 1 m to 5 km wide. This base is important because it is the most destructive part of a tornado. Sometimes several funnels extend down from the same cloud, causing great destruction. Multiple tornadoes from the same storm system in different places are not unusual.

Tornadoes can happen in any month, but in the southern United States most tornadoes occur in March through May. In more northern states, they occur most frequently in the summer. Most tornadoes touch down between 3:00 p.m. and 9:00 p.m., though they can appear at all hours of the day and night

A tornado may stay in one place, but it usually moves and can travel as fast as 100 kph! This is why you should never try to outrun a tornado in a car. Its direction of movement is usually from the southwest to the northeast, but it can move in other directions as well. At the same time, a tornado’s motions can frequently complicate the efforts of people trying to dodge it. It may sway from side to side and can lift up and touch down many times along its path. Sometimes the funnel is invisible until it actually touches down, but its funnel is usually white or gray. Its color often turns black as it touches the earth, picking up dust and debris and anything in its path. Lightning flashing twenty or thirty times per minute may accompany the tornado, and lightning may flash continuously inside the funnel.

TORNADO MIRACLES With every devastating tornado, there are stories of seemingly miraculous events—babies carried away and gently laid in a ditch, survivors tossed into a bathtub as the house fell around them and living to tell about it, or a row of houses completely flattened with the exception of one house left untouched. Do a web search and compile a list of tornado miracles.

Matthew 10:29, which says that every one of these events is directly under God’s control. Even as a fallen, broken world wreaks havoc, He still preserves life and property by His grace.

Each year about 1200 tornadoes strike the United

States, causing about 80 deaths and 1500 injuries.

The high-speed, rotating wind and the updraft are

the two great destructive features of a tornado. The

force of a tornado wind can take steel beams and

spear trees with them. Many times, after a tornado

has passed, people find that pieces of straw have

been driven like nails into trees or telephone poles.

The updraft within the funnel can lift people, animals,

automobiles, railroad cars, and even houses into the

air.

Rarely will a tornado simply move an object some distance and set it down

unharmed. It usually destroys whatever it touches. A tornado’s path of

destruction is usually narrow, but its whirling wind speeds may be as much as

515 kph—higher than in any other storm. Tornado strength or intensity is rated

on the six point Enhanced Fujita- Pearson (EF) scale. See Appendix I for a

detailed description of this scale. The EF rating is an estimate of the wind speed

that is based on the damage caused by the tornado, taking into account

construction materials and methods.

​Dr. Pearson further improved the original Fujita scale by adding indicators that describe the width of the destruction path and the distance that the tornado was in contact with the ground. Low pressure within the funnel of a tornado is not the destructive force it once was thought to be. In 2003, a researcher successfully placed a pressure-recording instrument in the path of an F4 tornado that measured a pressure drop of only 0.1 atm. Pressure inside even a powerful tornado is just a little lower than at sea level. So tornadoes don’t cause buildings to explode in low pressure. Other research and field observations have shown that a tornado’s high winds simply push the building’s windward walls inward. The tornado’s updraft lifts the roof off the building. The other walls fall outward due to the winds.

​Read this page