The Probability of a Major Hurricane Hitting New Orleans Table of Contents Executive Summary 3 Introduction 3 Hypothesis 7 Analysis & Method 8 Conclusion 10 References 12 Appendix 14 Executive Summary New Orleans, Louisiana lies at the second lowest elevation among major cities in the United States. It is a city surrounded by water, making it almost like an island. To counter this dangerous combination of the low elevation along with the lakes, rivers and swamps surrounding it, the Army Corps of Engineers built a series of levees around the city to foster its protection. It is these very same levees however that might doom the city should a Category 3 hurricane ever hit. Our statistical analyses examined the current belief that there is a 39% probability that New Orleans will be hit by a major hurricane and based on the resulting Z-score, rejected that belief. We did find however that the probability, while not 39%, was still in the 30 th percentile range, which should still be a major cause for concern among the leaders and residences of the city of New Orleans.
Introduction New Orleans is a city that is rich in culture as well as history. The city is in effect, an island – Lake Pontchartrain surrounds the city to the north, the Mississippi River to the west and south, and a bevy of lakes – including Lake Borne to the east. Surrounding the city is a series of levees to keep these bodies of water at bay. In addition to these levees, the only defense the city has is a series of canals and a very antiquated pumping system. However, the same levees that protect the city, makes it a death trap should a major hurricane make a direct hit to the metropolitan area. The risk of intense flooding brought forth by storm surges of 20+ feet would wipe the city out.
... This paper contrasts at length the city of New Orleans before and after Hurricane Katrina. New Orleans is geographically situated on a natural ... water from the Lake Pontchartrain up the levees and probably into New Orleans. The catastrophic destruction to New Orleans and its vicinity ... occurrence of Katrina, most of the major roads leading to and from the city were destroyed. The only route leading ...
Picture: web Orleans was founded to be a port to the world – with its intersection at the Mississippi River and the Gulf of Mexico, it was a great location for world trade. However, it was also a cesspool of disease, floods, and other problems. Despite this, the city was a major economic powerhouse and the city grew and prospered despite of the problems. As the city expanded, swampland was reclaimed to expand the city.
To protect its citizens, the Army Corp of Engineers built a series of levees around the city. These levees form a bowl around the city. It is precisely this architecture that was meant to protect the city will in effect destroy the city. What is a major hurricane? Hurricanes are measured using the Saffir-Simpson scale. The scale ranges from a Category 1 hurricane, which is the weakest, to a Category 5 hurricane, which is the strongest and most dangerous hurricane. The following chart illustrates the differences between the categories, which are measure by the winds of the hurricane.
Saffir-Simpson Scale Saffir-Simpson Category Maximum sustained wind speed Minimum surface pressure Storm surge mi / h m / s kt mb ft m 1 74-95 33-42 64-82 greater than 980 3-5 1. 0-1. 72 96-110 43-49 83-95 979-965 6-8 1. 8-2. 63 111-130 50-58 96-113 964-945 9-12 2. 7-3.
84 131-155 59-69 114-135 944-920 13-18 3. 9-5. 65 156+ 70+ 136+ less than 920 19+ 5. 7+Major hurricanes are those classified as a Category 3 (sustained winds of 111+ miles per hour or higher. ) Looking at the chart, the problem for New Orleans is evident – storm surge and the wetlands and barrier islands that are loss at an astounding rate every year. These wetlands and barrier islands work to slow down the storm surge and slow down the storm itself.
Without these barriers, water will push inland to New Orleans and spill over the levees. According to Walter Maestri in the Jefferson Parish (a suburb of New Orleans) emergency office, gives this scenario:’ The hurricane is spinning counter-clockwise, it’s now got a wall of water in front of it some 30 to 40 feet high, as it approaches the levees that surround the city, it tops those levees,’ describes Maestri. ‘The water comes over the top – and first the communities on the west side of the Mississippi river go under. Now Lake Ponchartrain- which is on the eastern side of the community-now that water from Lake Ponchartrain is now pushed on the population that is fleeing from the western side, and everybody’s caught in the middle. The bowl now completely fills and we ” ve got the entire community under water, some 20 to 30 feet under water.’ Remember all those levees that the U. S.
... 2002, New Orleans Times-Picayune released a five-part report on what could possibly happen if a major hurricane reached the city. As ... In August of 2005, the feared category 5 hurricane finally came. Hurricane Katrina began as a category 1 hurricane in August 25 when it passed ... to Louisiana. The warm waters of the Gulf of Mexico strengthened it turning it into a category 5 hurricane by early Sunday, ...
Army built around New Orleans, to hold smaller floods out of the bowl? Maestri says now those levees would doom the city, because they ” ll trap the water in. ‘It’s going to look like a massive shipwreck,’ says Maestri. ‘Everything that the water has carried in is going to be there. It’s going to have to be cleaned out- alligators, moccasins and god knows what that lives in the surrounding swamps, has now been flushed -literally-into the metropolitan area. And they can’t get out, because they ” re inside the bowl now. No water to drink, no water to use for sanitation purposes.
All of the sanitation plants are under water and of course, the material is floating free in the community. The petrochemicals that are produced up and down the Mississippi river-much of that has floated into this bowl… The biggest toxic waste dump in the world now is the city of New Orleans because of what has happened.’ To any other city in the United States, this scenario would cause damages like the 2004 hurricanes did to Florida. However, most cities are above sea level. New Orleans is as low as ten or more feet below sea level in some spots. This is the second lowest elevation in the country.
Surely, this is a doomsday scenario for the city of New Orleans, but what exactly is the probability that New Orleans will be swallowed up and claimed by the Mississippi and Gulf of Mexico – all because of the fury that is a major hurricane? The last direct hit was in 1965 by the Category 3 hurricane, Betsy. Hypothesis The purpose of this analysis was to determine the probability of a major hurricane hitting New Orleans. The current belief is that the probability of a major hurricane hitting New Orleans is 39%. As previously mentioned, a major hurricane is classified as a Category 3 or higher. The null hypothesis and the alternative were as follows: H 0: p = .
Hurricane Katrina (1) Nowadays, no American politician would ever speak to the public, without mentioning this countrys strong national unity or the fact that diversity makes us stronger. Yet, the objective reality points out at the notion of Americas national unity as nothing but a myth, because such unity disappears into the thin air, every time American large cities experience electrical ...
39 Ha: p. 39 The null hypothesis stated that the probability of a major hurricane hitting New Orleans is equal to 39%. The alternative hypothesis stated that the probability of a major hurricane hitting New Orleans is not equal to 39%. Analysis and Method A forecast by national forecaster William Gray of Colorado State University was used. A copy of the forecast is found in the appendix. In developing this criterion, a 95% confidence level was chosen.
The following formula was used: Z = Ps – P P (1-P) n The data used was a forecast of the total number of storms that should be experienced in the United States in 2005. According to the forecast, 20 storms are expected to hit in 2005. Of the expected 20 storms, 11 would be named storms, 6 would be hurricanes and 3 would be major hurricanes. A two-tailed analysis was performed. From the forecast, the following test statistics were obtained: Descriptive & Test Statistics Mean 6. 666666667 Standard Error 2.
333333333 Median 6 Mode #N/Standard Deviation 4. 041451884 Sample Variance 16. 33333333 Kurtosis Skewness 0. 722108646 Range 8 Minimum 3 Maximum 11 Sum 20 Count 3 Confidence Level (95. 0%) 10.
03953003 Null Hypothesis p = . 39 Level of Significance 0. 05 Major Hurricanes 3 Sample Size 20 Sample Proportion 0. 15 Standard Error 2. 333333333 Z Test Statistic 2. 201 Upper Tail Test Upper Critical Value 1.
96 p-Value. 39 Reject the null hypothesis The z test statistic is greater than the critical z value of 1. 96. We would therefore reject the null hypothesis and accept the default hypothesis. We are 95% confident that there is sufficient evidence that the probability of a major hurricane hitting New Orleans is not 39%. According to historical data, the probability of a hurricane hitting New Orleans is somewhere in the neighborhood of 30%.
The current hypothesis is based on the fact that between 1995 and 2004 there was an average of 15 tropical and subtropical storms, including nine hurricanes, six of which were major storms. New Orleans has been lucky over the past 25 years; however, meteorologists are starting to believe that the luck is about to come to a sudden halt. Conclusion Based on the historical data in conjunction with the statistical analysis presented in this project, the logical conclusion is that a major hurricane will be hitting New Orleans sooner, rather than later. While the data pointed to a rejection of the Null of 39%, the historical data shows that the probability is still in the 30% region. The historical data also points to the fact that New Orleans has been relatively lucky over the past 25 years.
Hurricane Katrina was a natural disaster that caused major damage to New Orleans. The Hurricane destroyed the city. “The storm also exposed historic tensions of race and class, and it produced deep mistrust of public officials and institutions” (Lukensmeyer, 2007). The whole city was flooded. The policy makers already had their minds made up on how they were going to rebuild Katrina. One of the ...
With the increase in the number of storms in recent years as well as an increase in intensity, the law of averages dictate that New Orleans is in danger of a major hit in one of the upcoming hurricane seasons. This analysis was done because a member of the team presenting this project is originally from the New Orleans area andis very concerned about this type of occurrence. Based on the data presented, including the geographical factoids relating to the levees around the city forming what can be described as a ‘bowl’, it behooves those in authority in New Orleans and its metropolitan suburbs to proactively have plans in place for a speedy evacuation of its residences during a major hurricane threat. While not much can be done about the current physical infrastructure of the city, its levees and surrounding waterways, a study should be commissioned that would look into a long term solution to what might some day become a catastrophic problem. The value of this project could be priceless if those in authority would heed the warnings the many experts cited, Walter Maestri of the Jefferson Parish Emergency Office and William Gray of Colorado State University, to name a few. Our project serves to support the findings of those gentlemen by presenting statistical data to corroborate the findings.
By showing that the Z-Score falls well the rejection zone, we are 95% confident that there is sufficient evidence that the probability of a major hurricane hit will not be 39%. Even so, the actual probability based on historical evidence still falls into the 30% range and that should be cause for major concern. References ” Gray And Colorado State Hurricane Forecast Team Call for Very Active September, Above-Average Season”, William Gray and Philip Klotz bach, Colorado State University. September 03, 2004.” Above-Normal 2004 Atlantic Hurricane Season Predicted”, NOAA National Hurricane Center, May 17, 2004.” United States Land falling Hurricane Project”, Tropical Research Project – Colorado State University, September 13, 2004.
Hurricanes are powerful atmospheric vertices that are intermediate in size. Hurricanes are unique and powerful weather systems. The word "hurricane" comes from a Caribbean word meaning "big wind." Views of hurricanes can be seen from a satellite positioned thousands of miles above the earth. Hurricanes originate as tropical disturbances over warm oceans with trade winds. The tropical turban ces ...
Hurricane specialist expects more storms in 2005 than in 2004, Florida Today, Jim Warmer, March 26, 2005. Berger, Eric. Keeping Its Head Above Water – New Orleans faces doomsday scene rio. December 1, 2001. Houston Chronicle. New Orleans.
Wikipedia. come. wikipedia. org / wiki /New Orleans Moyers, Bill. Transcript. PBS Printable Pages.
September 20, 2002. web full print. html McNamara, Dave/WWL-TV Reporter. Damage to city from powerful hurricane comparable to Asian tsunami Wednesday, January 12, 2005 web J. J and Luettich, R. A.
and all. The Creeping Storm. CIVIL ENGINEERING MAGAZINE. June 2003 Volume 73 Number 6 SIMPSON, DOUG Associated Press Writer. Faced with nightmare scenario, New Orleans empties ahead of Ivan SFGate.
com / September 14, 2004 web printer. shtml NATIONAL HURRICANE CENTER Hurricane forecasters analyze large amounts of data, including conflicting computer model results, and come up with their best estimate of a three-day track and intensity forecast. Just as it is easier to predict where you will be 12 hours from now as opposed to 72 hours, it is easier to predict where a hurricane will be right before it makes landfall (although hurricanes can, and do, unexpectedly alter course).
The figure below shows that, at shorter forecast time periods, the forecast track error is fairly small, but when the forecast is farther in the future, the error increases significantly. Knowing these estimated errors can help you assess your potential risk. AVERAGE TRACK POSITION FORECAST ERROR (1 nautical mile = 1.
15 statute miles) Forecasters convey track uncertainty through the strike probability tables and strike probability graphics which show the areas likely to be affected by the tropical cyclone. These products are based on the current best forecast track and the past distribution of errors. They are created to indicate the statistical chance that the hurricane center will pass within 65 NM (75 mi) of a location within 3 days of the initial forecast time. The maximum probabilities by forecast period are displayed in the table below and are based on NHC’s average forecast errors for the various periods. For example, if a hurricane is expected to make landfall in 48 hours at New Orleans, the highest the probability can be is 25%. Most coastal locations need to start evacuations by 48 hours in order to have them completed before the tropical storm-force winds arrive.
Hurricane, what does it mean? What do hurricanes do? What kind of powers do they possess? Where regions of the world are mostly affected by these hurricanes? All these questions I plan to answer in the following paragraphs. One thing we do know for sure is that a hurricane is one of the most devastating storms that Mother Nature has to offer. We also know that hurricanes cause a lot of damage to ...
In most cases, if you wait until the probability is 50% or greater, it will be too late to take effective actions. Consequently, this table provides critical information for decision making. Forecast Period Maximum Probability 72 hours 10%-15% 48 hours 20%-25%36 hours 25%-35% 24 hours 40%-50% 12 hours 75%-85% These probabilities are those which would be computed if the forecast position (at the given time period) were directly over a community. A range of probabilities is given because forecast errors differ by location. The probability can be 100% if the center is already close to a location.
In addition, the probabilities can exceed the maximums listed in the table if the hurricane center is actually forecast to be at the location at an earlier time period. Hurricane Intensity Forecasts Much like the difficulties in forecasting a hurricane’s track, hurricane specialists are challenged to predict the exact strength (in terms of wind speed) of a tropical cyclone. The average errors for intensity are shown below. AVERAGE INTENSITY ERROR BY FORECAST PERIOD (1 nautical mile = 1. 15 statute miles) Hurricane Warning Area Size of the warning area and timing of the warnings are based on the forecast track, the size of the storm, and the known uncertainties in the forecasts. o Orientation of the forecast track with respect to the coast plays a major role in the size of the warning area.
NWSNOAAFEMA web WATCHES & WARNINGS This display shows an approximate representation of coastal areas under a hurricane warning (red), hurricane watch (pink), tropical storm warning (blue) and tropical storm watch (yellow).
The orange circle indicates the current position of the center of the tropical cyclone. The black line and dots show the National Hurricane Center (NHC) forecast track of the center at the times indicated. The NHC forecast tracks of the center can be in error, and the white area indicates the average area of uncertainty for the position of the center. It is important to realize tropical cyclones are not a point.
Their effects can span many hundreds of miles from the center. The area experiencing hurricane force (one-minute average wind speeds of at least 74 mph) and tropical storm force (one-minute average wind speeds of 39-73 mph) winds can extend well beyond the white area shown enclosing the most likely track area of the center. The distribution of hurricane and tropical storm force winds in this tropical cyclone can be seen in the Cumulative Wind Distribution graphic displayed below. STRIKE PROBABILITIES This is an experimental product. This display shows the probability, in percent, that the center of the tropical cyclone will pass within 75 statute miles of a location during the 72 hours beginning at the time indicated in the caption. The caption also provides the name of the tropical cyclone and the advisory number from which the probabilities were generated.
Contour levels shown are 10%, 20%, 50% and 100%. CUMULATIVE WIND DISTRIBUTION This display shows how the size of the storm has changed, and the areas affected so far by tropical storm and hurricane force winds, in orange and red, respectively. It is based on information contained in the set of advisories indicated in the caption at the top of the figure. Note that the display is based on estimated coverage of one-minute average winds, not gusts. WIND SPEED FORECAST AND PROBABILITY CHART This is an experimental product. It shows the National Hurricane Center (NHC) maximum 1-minute wind speed forecast as a broad blue line on a chart of wind speed versus forecast period.
The narrower lines, labeled 10% and 20% (or 30%), indicate the probability that the maximum wind speed will be some other magnitude than what the NHC has forecast. For example, the cyclone could become stronger than the NHC has forecast, with there being a 10% chance that the wind speed will attain the level indicated by the 10% line plotted above the NHC forecast. The probabilities are based on NHC forecasts from 1988-1997. The data base excludes unnamed tropical depressions. Current advisory information is shown near the bottom of the chart.
When applicable, the Saffir/Simpson Hurricane Scale is shown at right. ‘Inland’ is indicated for periods when the cyclone center is forecast to be over land. ‘Ext’ indicates that the NHC forecasts the cyclone to be extra tropical at that time. WIND SPEED PROBABILITY TABLET his is an experimental product. The table shows the probability that the maximum 1-minute wind speed of the tropical cyclone will be within any of eight intensity ranges during the next 72 hours. It is based on the outcomes of similar NHC wind speed forecasts during the period 1988-1997.
The data base excludes unnamed tropical depressions. NA indicates data not available. TF indicates too few (.