Atmosphere And Weather

Tornadoes and Hurricanes – Tornadoes



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Statistically tornadoes kill more people in the United States than hurricanes. For this debate, I am assuming that we are referencing the U.S. and not worldwide, although there can be an argument made for either.

As for the United States, an average of 1,100 tornadoes occur each year. This year (so far) has proven to be much above the average. Three reasons that tornadoes are deadlier in this country in particular are the unpredictability of tornadoes, lack of sufficient shelter, and arguably most importantcomplacency.

One recent example occurred June 11th at a Boy Scout camp near Little Sioux, Iowa. Four Boy Scouts were killed and dozens injured in a high EF2 or low EF3 tornado. The survivors claimed there were only seconds to take cover. The question remains, why so little time? The Nation Weather Service in Omaha had issued a tornado warning for the area at 6:23 local time and the camp was struck at 6:45. That is a 22 minute warningexcellent lead time for a tornado and ample time to seek shelter, yet young men died.

There is a finger of blame to be pointed, however the question is where? Was the camp equipped with a weather radio, or a landline telephone? Given the remoteness of the area and the fact that the area was under a tornado watch, either of these two things could have been utilized for a much more advanced warning. During the peak season, tornado warnings in tornado alley are commonplace. People tend to ignore them and go about their routine until a tornado is actually sighted. A dangerous practice considering that tornadoes can be hidden by rain, or lack a condensation funnel and remain virtually invisible. Was it the complacency of the troop leaders that caused this tragedy?

There are shelters specifically designed to prevent injury and death in a tornado. Was one in place at the camp site? I propose that all recreational areas and campgrounds should provide such shelter. With a sufficient shelter and sufficient lead time, this tragedy could have been prevented.

Although the conditions for tornadoes can be easily determined, it is impossible to accurately predict when or where one will touch down in a particular area. Doppler Radar can detect rotation in the storm, but Doppler is limited in its capacity to determine if there is a tornado on the ground. Spotters are crucial to aid the NWS in this capacity. Doppler may also be used to predict a theoretic path, however, tornadoes can meander and even travel in loops. One example could be the outbreak on June 3rd, 1980 in Grand Island, Nebraska.

Over a two hour period, as many as seven tornadoes touched down in or near the city of Grand Island, killing 5 and devastating much of the city. This event was meticulously studied by the foremost authority on tornadoes of the time, Dr. Tetsuya Fujita, who designed the damage scale for tornadoes. He determined that the tornadoes that night performed loops, or stayed stationary at times. This caused many meteorologists to rethink their understanding of tornadoes.

The benchmark for tornadoes occurred March 18th, 1925. The tornado touched down in Reynolds County, Missouri and stayed on the ground with no break in the damage path until it dissipated near Princeton, Indiana some three hours later. Nearly 700 were killed and thousands injured in its path. It was determined that at one time the tornado had a forward speed of 73 mph! In that era there was little possibility of warning people in the path. One can only guess what the death toll would be had it occurred with today's technology.

On average, only one or two tornadoes are categorized as EF5 in any given year. However, on April 3rd of 1974, the day of the famous "Super Outbreak", six tornadoes were classified as F5's and an amazing 148 tornadoes touched down in a 20 hour period. It began in Morris, Illinois and ended in North Carolina in the early hours of the 4th. Nearly 350 died and perhaps four times that many were injured. NOAA officials in Kansas City could see the conditions coming together, but could only guess at the areas affected. They did what they couldinforming local NWS offices to ensure their radar equipment was calibrated and in working order. No one could guess the enormity of the scale of the disaster.

As with all weather events, the forecasting of hurricanes has advanced considerably since weather records began. Most early warnings were provided by shipping vessels, which telegraphed their weather conditions to the weather service office, then in Washington D.C. and what sparse information (if any) was gleaned from the freighters was then relayed to the endangered.

Early hurricanes were impossible to predict and many disasters of near biblical proportions struck the United States mainland. Of the top 10 deadliest hurricanes, only one occurred after 1950. Other, more current hurricanes have caused much more damage and have been more intense than earlier, deadlier hurricanes. The warning system is much improved which has lessened the loss of life.

Specially equipped planes can fly into the eye of today's hurricanes, culling much better information on intensity and other important measurements than ever before. Warnings are much more accurate, with forecast models aiding in the prediction of land falling hurricanes. Houses can be cheaply reinforced to reduce damage and with recent disasters such as Katrina, the public has become more prone to evacuation.

Lead times are much longer with hurricanes. Hurricane hunter aircraft are essential for flying into suspicious developments when conditions are favorable and aid in the determination of whether a particular disturbance will evolve into a hurricane. Often, stalled fronts or other weather conditions will turn the hurricane out to sea where they die out in the colder waters in the North Atlantic.

Hurricanes are also more prone to develop during hurricane season, beginning officially the first day of June for the Atlantic and Gulf Coasts. In the early part of the season, officials watch closely for development in the Gulf and Caribbean. As the water warms, the danger zone extends all the way to the west coast of Africa in the what is called the Inter-tropical Convergence Zone. This is known as the Cape Verde season. Officials have a much longer time to watch suspicious systems as impulses leave the African continent.

While tornadoes occur mostly through the spring and early summer months, there is no definitive season. In the Southern U.S., the most dangerous months would likely be February and March. The season will progress north as the warmer Gulf air becomes more established. The South is especially vulnerable because a larger percentage of the population live in mobile home parks and tornadoes tend to occur much later into the evening than they do in the Middle Mississippi Valley. The Mississippi Valley region is more prone in the months of April and May, moving into the Northern U.S. in late May and June. Eventually making its way into Canada in June and July.

Then there is almost a second season as the warm air recedes and the cooler Canadian air pushes back in from the north. These facts are merely gleaned from statistics. It is not uncommon for tornadoes to develop anywhere during the course of any given year. F5 tornadoes have occurred as far north as Southern Illinois in mid-December.

Ironically, in some areas that experience a higher rate of tornadoes, bedrock lies only a foot or so beneath the groundmaking homes with basements an exception rather than the rule. This is particularly true of parts of Texas and Oklahoma. Here is where special rooms are designed as tornado shelters. Newer homes are now being built with these specially designed roomsusually a closet near the center of the home. In existing homes, steel reinforced concrete shelters can be built just outside the dwelling and anchored into the bedrock. As this becomes more common, deaths and injuries will hopefully become fewer.

There will come a day when a tornado impacts a major metropolitan area at the worst possible time. Oklahoma City is nearly 250% more likely to be impacted by a tornado than the United States average! If an EF5 tornado moves into a city such as this during rush hour it could prove to be a worst-case scenario. Consider uninformed people taking cover under an overpass on a major thoroughfare, "tornado jams" may be likely to occur. A still common misconception is that an overpass is safe. Commuters will actually block the roads and scramble for what they consider to be safety, cutting off any routes for escape to a viable shelter. Imagine for a moment a quarter to half mile wide EF5 tornado barreling straight down an interstate highway into a fully packed tornado jam. Since 1953, no single tornado in this country has killed more than 100 people. It isn't a question of "if" but "when" this will happen again. Emergency vehicles will have limited or no access to the affected area and possibly hundreds would die outright and many more may die just waiting for aid.

Unpredictability, time and complacency will eventually lead to such a disaster. While the storm surge of a hurricane is where most lives are lost, it is flying debris that kills and injures most tornado victims. These factors make tornadoes a much deadlier meteorological event than hurricanes.

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