Hurricanes and tornadoes are both stormy atmospheric systems that have the potential to cause destruction. They are caused by instability in atmospheric conditions. According to the region and severity of stormy conditions, hurricanes may also be referred to as typhoons or tropical cyclones.
|About||A hurricane is a cyclone that is located in the North Atlantic Ocean, or the NE Pacific Ocean east of the International Date Line, or the South Pacific Ocean east of 160E, and with sustained winds that reach or exceed 74 mph.||A tornado is a rotating column of air ranging in width from a few yards to more than a mile and whirling at destructively high speeds, usually accompanied by a funnel-shaped downward extension of a cumulonimbus cloud. Winds 40-300+ mph.|
|Rotation||Clockwise in the southern hemisphere and counterclockwise in the northern hemisphere||Clockwise in the southern hemisphere and counterclockwise in the northern hemisphere|
|Intensity||Hurricanes are classified into five categories according to the Saffir-Simpson Hurricane Wind Scale. The wind speed and intensity of damage increases as from category 1 to category 5.||The scale used for rating the strength of tornadoes is called the Fujita (F), Enhanced Fujita (EF), and TORRO (T) Scale.|
|Location||North Atlantic Ocean, the Northeast Pacific Ocean east of the International Date Line, or the South Pacific Ocean east of 160E. Hurricanes are found near the tropical zone, over warm waters in the Atlantic and Pacific ocean.||Tornados have been spotted in all continents except Antarctica.|
|Most affected areas||Caribbean Sea||In areas where a convergence of cold and warm fronts is common. i.e. US Midwest.|
|Frequency||10-15 per year||The United States records about 1200 tornadoes per year, whereas the Netherlands records the highest number of tornadoes per area compared to other countries. Tornadoes occur commonly in spring and the fall season and are less common in winters|
|Occurrence||Usually warm areas||Places where cold and warm fronts converge. Can be just almost anywhere.|
|Characteristics||Heavy winds, floods, storm surge, a lot of rain, tornadoes||Very strong cyclonic winds, very heavy rain, large hail, strong cloud to ground lightning.|
|Forms of precipitation||Rain||Rain, sleet, and hail|
|Number of convective storms||Several; could be dozens||One|
|Temperature gradient required||Small; near zero||Large|
|Life span||In days||In minutes|
|Size||Diameter of hundreds of kilometers||Diameter of hundreds of meters|
|Amount of warning||Days to weeks. The exact area of which the hurricane will hit is known within days, but the storm system will last for significantly longer than that, with changes in its path frequent.||Minutes to hours. The conditions for the possibility of a tornado can be predicted hours before an event, however, tornadoes rarely leave much more than a couple minutes warning. And sometimes none.|
|Shape||Symmetrical with often clearly defined center.||Cone shape.|
Definitions of Hurricanes and Tornadoes
A hurricane is a type of tropical cyclone with sustained winds that exceed 74 mph and accompanied by rain, thunder and lightning.
A tornado is defined in the dictionary as "a rotating column of air ranging in width from a few yards to more than a mile and whirling at destructively high speeds, usually accompanied by a funnel-shaped downward extension of a cumulonimbus cloud". The wind speeds of tornadoes range from 40 mph to 110 mph, span about 75 m across and can travel a few miles. In extreme cases, tornadoes have also reached a speed of 300 mph.
Hurricanes are found near the tropical zone, over warm waters in the Atlantic and Pacific ocean. Tornadoes have been spotted in all continents except Antarctica though a large number have been seen in the United States.
Characteristics and types
Hurricanes develop over ocean water warmer than 26.5 °Celsius and heat and moisture from the ocean forms the basis of this type of storm. Thus, hurricanes weaken rapidly over land and over cold waters, which cannot provide enough heat or moisture to sustain this storm. The low pressure centers of hurricanes are known as the "eye" and are warmer than their surrounding areas. The eye is surrounded by strong winds and rain and this area is called the "eye wall". Hurricanes have no fronts. The hurricane season peaks from the middle of August to late October in the Atlantic Ocean.
There are many shapes and sizes of tornadoes. Tornadoes look like big funnels low in height with a cylindrical profile are referred to as stovepipe tornadoes, whereas those that are like large wedges stuck to the ground are called wedges. Tornadoes can also be a small swirl of dust close to the ground and not easily identifiable. Similarly tornadoes can assume twisted and rope-like shape that narrow and extends from the clouds down in a long and narrow tube like fashion; these are referred to as "rope tornado". Tornadoes with more than one vortex can swirl around one common center and appear as a single funnel. The types of tornadoes include multiple vortex, waterspout, gustnado, dare devil, fire whirls and steam devils.
The color of the tornadoes varies according to the region they occur in and depends on the color of the soil and debris collected. For instance, tornadoes with little debris appear gray or white, tornadoes in the Great Plain have a reddish hue because if the color of the soil, and tornadoes that occur in the mountainous snow-covered region turn white.
Tornadoes require substantial vertical shear of the horizontal winds (i.e. change of wind speed and/or direction with height); tropical cyclones (including hurricanes) require very low values (less than 10 m/s [20 kt, 23 mph]) of tropospheric vertical shear in order to form and grow.
Tornadoes are produced in regions of large temperature gradient, while tropical cyclones are generated in regions of near zero horizontal temperature gradient. Therefore tornadoes typically occur over land (where the sun's heat can produce the required temperature gradient) while tropical cyclones are an oceanic phenomenon. Hurricanes lose momentum after land fall because the required moisture is not available on land.
Hurricanes and Tornadoes turn clockwise in the Southern hemisphere and counterclockwise in the northern hemisphere.
The lifespan of a tropical cyclone (hurricane) is in days while a tornado lasts only a few minutes.
The diameter of a tornado is hundreds of meters. It is powered by one convective storm. On the other hand hurricanes span hundreds of kilometers and comprise several convective storms.
Intensity and Damage
Hurricanes are classified into five categories according to the Saffir-Simpson scale. The wind speed and intensity of damage increases as from Category 1 to category 5. Category 1 hurricanes cause minimal damage with wind speeds of 74-95 miles per hour (mph), category 2 cause moderate damage with wind speeds varying from 96-110 mph, category 3 cause extensive damage, with wind speeds of 111-130 mph, category 4 causes extreme damage with wind speeds of 131-155 mph, and category 5 has catastrophic damage with wind speeds of over 155 mph.
The intensity of tornadoes can also vary in intensity those with a longer track being stronger. The scale used for rating the strength of tornadoes is called the Fujita (F), Enhanced Fujita (EF), and TORRO (T) Scale. The range varies from F0, EF0 or T0 for minimal damage (damages trees but not buildings) up to F5, EF5 or T11 for vast degree of damage (buildings and skyscrapers end up getting damaged).In the United States, maximum tornadoes (80%) fall into the EF0 and EF1 (T0 to T3) category and less than 1% are violent (EF4, T8 or more).
In the Atlantic ocean, hurricanes occur about five or six times a year. The Caribbean is a focal area for many hurricanes. A series of low pressure systems develop off the West coast of Africa and make their way across the Atlantic Ocean. While most of these systems do not become tropical storms, some do. The Caribbean hurricane season is from June through November, with the majority of hurricanes occurring during August and September. On average around 9 tropical storms form each year, with 5 reaching hurricane strength. According to the National Hurricane Center 385 hurricanes occurred in the Caribbean between 1494 and 1900.
The United States records about 1,200 tornadoes per year, whereas the Netherlands records the highest number of tornadoes per area compared to other countries. Other countries that have frequent occurrence of tornadoes include South Africa, Paraguay, parts of Argentina, and parts of Europe, Australia and New Zealand. Tornadoes occur commonly in spring and the fall season and are less common in winters.
Hurricanes and tornadoes are detected by Pulse-Doppler radar, photogrametry, and ground swirl patterns.
- National Oceanic and Atmospheric Administration - The difference between a tropical cyclone and tornado
- Hurricane Tracker - Wall Street Journal
- All hurricane names since 1950