Tornado, Hurricanes, Condition, Hurricane, Storm

Tornado

A tornado is a violently rotating column of air that is in contact with the both the surface of the earth and a cumulonimbus cloud or, in rare cases, with the base of the cumulus cloud. They are usually referred to as the twister or the cyclone, although the word cyclone used in meteorology, in a wider sense, to name any closed low-pressure circulation. Tornadoes come in many shapes and the sizes, but they are typically in the form of a visible condensation funnel, whose narrow end touches the earth and is often encircled by a cloud of debris and the dust. Most tornadoes have the wind speed less than 110 miles per hour i.e 177km/hr and are about 250 feet(76m) across and travel a few miles i.e several kilometres before they have dissipating. The most extreme tornadoes can attain wind speeds of more than 300 miles per hour(483km/hr), which are stretch more than two miles i.e 3.2km across and were stay on the ground for dozens of miles i.e more than 100km.

Various types of tornadoes include the landspout, multiple vortex tornadoes, and the water spout are found. Water spout is characterised by a spiralling funnel-shaped wind current, with connecting to a large cumulus or cumulonimbus cloud. They are generally classified as not-supracellular tornadoes that have to develop over bodies of the water, but there is the disagreement over whether to classify them as true tornadoes. These spiralling columns of air frequently develop in the tropical areas close to the equator and were less common at high latitudes than other tornadoes like phenomena that were exist in nature include the gustnado, dust devil, fire whirls and steam devil.

Tornadoes have been observed on every continent except Antartica in whole . However, the vast majority of the tornadoes in the world occur in the so-called the "Tornado Alley" which is the region of the united states, although they can occur nearly anywhere in the north America. They also occasionally occur in the south- central and eastern Asia, as well as in northern and the east central south America, southern Africa, northwestern and south-east Europe, western and the south-eastern Australia and the new Zealand. Tornadoes can be detected before and even as they occur through the use of the plus doppler radar by recognising the pattern in the velocity and reflectivity data, such as hook echoes as well as by the efforts if the storm spotters.

There are several scales for rating the strength of the tornadoes. The Fujita scale rates tornadoes by the damage caused and have been replaced in some countries by the updated enhanced Fujita scale. An F0 or EF0 tornado is the weakest category damages trees but not substantial structure. An F5 or EF5 tornado, are the strongest category, rips buildings off their foundations and can deform large skyscrapers. The similar TORRO scale ranges from a TO for extremely weak tornadoes to T11 for the most powerful known tornadoes. Doppler radar data, photogrammetry, and ground swirl patterns i.e cycloidal marks may also be analysed to determine the intensity of tornado and assign a rating to them.

Hurricanes :

A hurricane is a tropical storm with the winds that have reached a constant speed of 74 miles per hour or more than that. The eye of the storm is generally 20-30 miles wide and maybe extend over 40 miles. The dangers of a storm include torrential rains, high winds, and the storm surge as well.

A hurricane can last for 2 weeks or more than that over open water and can run a path across the entire length of the eastern seaboard.

Emergency information.

The 74 to 160 mile per hour winds of a hurricane can extend inland for hundreds of miles. Hurricanes can spawn tornadoes which add to the destructiveness of the storm. Floods and flash generated by torrential rain also cause damage as well as the loss of the life. Following a hurricane, inland streams and the rivers can flood and trigger landslides.

• When a hurricane watch is issued, to be yourself safe the best response is to protect our property by boarding up windows, bringing in outside items and being prepared to evacuate the areas as soon as officials so advise.
• Even more dangerous than the high winds of hurricanes is the storm surge which is a dome of ocean water that can be 20 feet at its peak and 50 to 100 miles wide. This type of surge can devastate coastal communities as it sweeps as the shore. Nine out of the 10 hurricanes facilities are attributed to the storm surge which is regarded as dangerous.
• The primary hazards of a hurricane are the storm surge, high winds, debris, tornadoes, and rain or flooding as well which are very devastating.

Conditions which must be present are as follows

• The condition must be in Low-pressure system
• Warm temperatures over the ocean should be maintained.
• Moist environment i.e precipitation should be present in order to fulfil the need.
• Tropical wind patterns over the equator are needed.

Statistics of storms

• On the average 100 tropical disturbance develop each year between in the May and November over the Atlantic Ocean. Half of these begin over Africa near the Cape Verde islands.
• About almost of 25 of these disturbances develop into tropical depressions to form tropical storms.
• Out of these 25 tropical depressions, 10 become tropical storms in average.
• Out of these remaining 10 storms, only 6 become hurricanes in real but they do not strike the coast of US.
• Out of these 6 hurricanes, 2 are likely to strike the coast of the Unites States.

Season

The Atlantic hurricanes seasons begin on June 1 and ends up with the November 30 of the each year.

An early hurricane occurs in the first three months of the season i.e June-August while the late hurricanes occur in the last three months of the season i.e September-November. Historically, the most active time for the hurricane development is the mid-August through the mid-October. The winter hurricane threat is virtually non-existent. Since 1886, only 3 hurricanes have been officially recorded during the month of December and only 1 during the month of the January.

Strength and intensity of hurricanes

The strongest hurricane recorded was the Florida key storm of 1935. Five hundred people killed from the category five storm

The largest storms recorded were the category 5 Labor Day storm of 1935, which killed four hundred in Florida and Hurricane Camille that hit the Louisiana and Mississippi in 1969. Camille caused a twenty-five-foot storm surge and killed 256 and caused the flooding all the way to the New England.

In general, hurricanes lose about ½ of their intensity in the 12 hours after the landfall, Hugo, which hit the north and the south of the Carolina in 1989 had a 20-foot storm surge and caused damages in the amount of $7 million. Storm surge, the raising of the ocean water along with the storm tide, is the leading killing element during the hurricanes.

References:

.S.C., Santee. Environmental Science. India, New Center: New Center Book Agency (P) Ltd, 2004.

Lal, D.S. Climatology, Sharda Pustak Bhawan, Allahabad.(2010)