Date of Submission
Statistical analysis of Tornadoes of Arkansas
This project report gives chronological accounts of tornadoes events that have occurred over a period of 33 years, which is from 1980 to 2013. The paper is meant to illustrate statistical analysis of spatial and temporal occurrences of the mentioned environmental disaster. The rationale of the study was to give reasons behind the high instances of tornado related events and to formulate recommendations on how to predict the occurrences to reduce casualties and damage to property. Again, the analysis would build the foundation for modeling of future changes of a natural disaster with the aim of enhancing communication and disaster preparedness. The results from the study were used to test the hypotheses as enlightened in the paper. The variables for formulating the hypotheses were terrain features, particularly valley orientations. Secondary data were sourced from the National Weather services database. Both quantitative and qualitative statistical analysis of the historical accounts of data on tornadoes formed the basis of the research. The study area was majorly the state of Arkansas, but to create a relational picture that would facilitate contrast and comparison; the Southern Missouri was also studied. The latter formed the baseline for relational analysis. The findings of the study were analyzed by use of regression tools to confirm whether the variables used were correlating or not, to support or disapprove the hypotheses. The results from the research show that, for all this long period, occurrence of tornadoes has proved to be in a way consistent, but variable in intensity (Grazulis 234).
IntroductionTornadoes are violently spinning air vortices that extend from very high to extremely severe thunderstorms towards the surface of the earth. The environmental events are very destructive when they strike because tornadoes results to a lot of injuries, deaths, and loss property worth of millions of dollars. Areas where tornadoes are prevalent are commonly known as ‘Tornado Alley.’ Despite occurring in the vast parts of the world, tornadoes are known to be highest in the United States (Gallimore 5). Although Arkansas has never appeared in the list of areas with the infamous Tornado Alley, which is commonly known to stretch from the Northern part of Texas northward via Oklahoma, Nebraska, and Kansas, Arkansas has been hard hit. So many devastating outbreaks of tornadoes have affected the state of Arkansas to very high extents (Grazulis 237).Tornadoes cause a lot of extreme heat, which leads to high humidity. The conditions have got severe health risks to the people who are not acclimatized to those particular conditions. A population that is not able to effectively cope is also highly affected (Gallimore 7-11). Consequently, extremely warm days lead to a lot of troubles, which are coupled with variability in adverse environmental conditions. The events also lead to an irregular distribution of summer temperature anomalies that result to intense radiations. In terms of extent of exposure and negative effects, the socially vulnerable groups suffer the most because they possess limited coping capabilities (Berry 37)This report on tornado genesis gives history bound events on temporal and spatial accounts of the Arkansas state to prove or dispute the hypotheses that try to explain the causative agents of the tornadoes. There are estimate evidences that the topographical orientation of the state is the main reason for the frequent and consistent tornadoes (Gallimore 30).Some literatures have linked the disaster incidences to land cover changes that are majorly influenced by human activities (Grazulis 241). These accounts see people as both direct and indirect agents of causation. It is worth stating that this research goes extra miles to use the most technological tools and instruments that raise that accuracy and reliability of the results.Hypotheses of the studyThe findings from this report were geared towards supporting or disapproving the following hypotheses. They are both null and alternative, however, all of them give statements that look for answers of whether the variables involved correlate or not.1. Alternative -Topographical orientation of Arkansas State is the reason for occurrences of the tornadoes.2. Null – Topographical orientation of Arkansas State is not the reason for occurrences of the tornadoes. Research questions1. Is there a relationship between the physical orientations of Arkansas with the frequent tornadoes?2. Are land cover systems related to the events of tornadoes?3. What are the impacts of the tornadoes?4. What is the chronological account of the incidences of the environmental disasters?5. What is the pattern of variation in the intensity of the tornadoes?
6. What is the effect of population on the numbers of tornadoes per unit area? Rationale for the StudyThe main reason for the study was to know why the destructive tornadoes are prevalent in the state of Arkansas. The information is very critical for long-term modeling of future chances of tornado events and how to counter them. When we source the relevant data and analyze, accurate predictions are enhanced and this forms the center stage for initializing adaptive mechanisms. Subsequently, relevant information on the most vulnerable regions of the state will guide the policy maker to prioritize on their interventions (Berry, 56). The leaders of Arkansas will also find the results resourceful in enhancing fair and equitable distribution of relief food to the affected population. The general idea behind the study is to ensure that people cope, survive, and adapt in case of the occurrences. The finding might also be used to create a database of the tornado cases. This will further improve or change the provisions of the previously available archive information. The study may also open other avenues for future studies.Literature reviewTornado intensity has normally in a traditional way been measured in accordance to the Fujita Scale (F-scale). That was based on the extent of damage to structures. The ranges are given from F0 to denote a weak one to F5 that corresponds to the extreme levels. Even though the technique is good for measuring the intensity, it has some setbacks since some strong tornadoes do not hit structure or variation in the strength and stability of structures might deter or minimize damages (Gallimore 87). However, enhanced Fujita scale has been developed to address the discrepancies. Between the years of 1950 and 2006, more than two hundred F4 magnitude tornadoes have been recorded. This gives a preliminary data on how so many high intensity cases have struck the state of Arkansas (Grazulis 243-247).Tornado has caused immense problem to the state of Arkansas since the nineteen eighties to date. In January 1999, the state experienced the highest hit of tornadoes on any single January day (Gallimore 90-94). It was in this month of the year when this state suffered the largest single strike that ever affected it. In first March 1997, the disaster led to about twenty-five fatalities, however, that the incident was less intense as the case of 1999. Throughout the change of time, so many deadly cases have resulted to so many deaths and injuries.In the early times of the twenty-first century, almost up to six hundred and twenty two tornadoes in the state killed close to thirty-nine persons and around five hundred and forty injuries (Grazulis 256). Additionally, massive property damage was noted that accounted to cash greater than six hundred and fifty million dollars. In particularly, in the second month of the year 2008, an EF-tornado destroyed a linear millage of path of approximately 123 miles in seven counties of north-central Arkansas (Skiles, Newton, and Gary 44). The 2008 hit also led to 880 homesteads damaged and up to one hundred business turned to useless property. The same event resulted to so many causalities as 20 people died and harming more than 140.Some severe cases also occurred in the years of 2002 through to 2005 when the remnants of hurricane initiated about seventeen tornadoes that moved towards the northwest from the southeast. This was very unusual to the residents and spurred a lot of fear and a sense of vulnerability. Some people opted to evacuate in search of safety and survival. A normal tornado affects a spatial scale on the ground to about a mile, but the tornadoes of the three years stretched to the point of up to seventy-seven miles (Skiles, Newton, and Gary 84). The intensities automatically usher in to us the idea of the extents of damages and other subsequent impacts.In the year of 2011, more than sixty cases were reported, which lead to eleven deaths. Distinctively, in February that year, five people were killed by twenty-five tornadoes that struck the county of Faulkner. Moreover, in the same year in May a 47 mile tornado affected drastically the counties if Johnson and Franklin (Skiles, Newton, and Gary 60-72).The study of tornadoes needs the understanding of the distribution. All the sections of Arkansas have been reported to be struck by tornadoes. Nonetheless, records on highly populated areas have been higher than the rural areas, which are covered with forest and are mountainous. A positive correlation (r=45) occur between the population of people to the number of tornadoes per unit area (Skiles, Newton, and Gary 108). Other factors that affect tornado incidences include; changes in population, communication facilities and land cover systems.Data and Methods
Statistical daily weather conditions for several Arkansas area weather stations were obtained from the National Weather Service (NOAA). Through the weather stations, complete and consistent data for the state of the daily tornado touchdowns from 1980 to 2013 were collected. These data were filtered to compose of values F-scale ≥ 1 and tallied to obtain yearly totals of weak to strong touchdowns. A subset of extremely strong intensity cases (F ≥4) was also compiled (Gallimore 91-103). To obtain the annual summation of the number of tornadoes, individual monthly events were added and averaged to derive the annual average number of tornadoes. The distributions of normal and abnormal incidences were examined through analyzing their skewness in distribution curves. Measures of average tendencies (mean, mode and median) were therefore determined to facilitate analysis.
Probability curves were then drawn to show normal distributions or anomalies. They were developed from the number of annual touchdowns in different periods of time to ascertain changes in occurrences. The binomial probability curves of the ranges of touchdowns, either in terms of numbers or intensities facilitated comparison and contrast analysis. The area of study as mapped is shown in appendix 1 and a graph from the weather station is given in figure 1. These data were essential for the study that led to generations of results as given in the other section of this paper.
Fig 1: shows data from the National Weather service on the events of tornadoes from 1980-2011
Fig 2: shows a photo of a section that had been struck by a tornado.
Figure 3: Clustered hotspot region showing areas of extremely high tornado cases
Figure 4: shows the number of tornado cases from 1980-2000
Figure 5: shows the number of tornado cases from 2001-2013
Table 1: shows tornado cases and their effects
Date(s) (yyyy-mm-dd) Tornadoes Fatalities Highest Fatalities Injuries Highest Injuries Longest Path Widest Path
1950-01-13 – 2013-12-21 1714 386 people 50 people5392 people 364 people121.84 miles2900 yards FindingsThe area struck by tornadoes experience a lot of property damage (figure 2). The damage to structures and business premises not only affect the individuals but also the government. The leaders of the respective counties or the overall state must ensure prompt response to evacuate the victims or offer the relevant logistics.
Skewness in the distribution is illustrated in figure 3, the visual outlook gives information that the period studied was accompanied by variability in the number of the tornadoes. The insight is that, the factor (s) that cause tornadoes also vary with time.Figure 4 show that the most severe cases of tornado occurred in the years of 1982 and 1999. It, therefore, means that, in the years, more deaths and infrastructural damages were experienced.In figure 5, 2003, 2005, 2008, and 2011 were accompanied by so many tornadoes. But, the entire graph depict that, from 2001, so many tornadoes had struck Arkansas. This can be attributed to increased populations and diverse industrial activities that degenerate defensive mechanisms such as forests.Table 1shows that the intensities of the tornadoes vary and the variation determine the extent of damage and fatalities. Those with high F-scale will cause the worst havoc that might lead to deaths, injuries and economic losses.In general Arkansas is one of the very unfortunate states of the United States because of the annual and consistent cases of tornadoes. For those who live in Arkansas, they have acclimatized themselves with the pattern of occurrences. However, this study had some limitations, for instance, there was a correlation of the variables (landscape, forests and population) with the number of tornadoes, but these do not clearly define causations. ConclusionTornado is a natural phenomenon, but the cases are accelerated by human activities. Some socio-economic factor such as population influences the number and intensity of the tornadoes. All the variables that were regressed against the occurrences of tornadoes per unit time showed a positive correlation. The dependent variable included population, forest cover and physical relief. The study, therefore, supports the alternative hypothesis, by asserting that, there is a positive correlation between the occurrence of the tornado and the physical feature. Therefore, it is concluded that the physical landscape of the state of Arkansas is responsible for its high cases of tornadoes.
Berry, Trey. The Arkansas Journey. Salt Lake City: Gibbs Smith, 2007. Print
Gallimore, Robert G. Topographic Influence on Tornado Tracks and Frequencies in Arkansas and Wisconsin. , 1968. Print.
Grazulis, T P. The Tornado: Nature’s Ultimate Windstorm. Norman: University of Oklahoma Press, 2003. Print.
Skiles, Newton K, and Gary Huitink. Tornado Safety. Little Rock, Ark.: Cooperative Extension Service, University of Arkansas Division of Agriculture, U.S. Dept. of Agriculture, and county governments cooperating, 1994. Print.
Appendix 1: the map of the research area