1. Figure1 shows the hourly distribution of tornado frequency in the UpperMidwest. Over what 1-hour period(s) do tornadoes occur mostfrequently in the Upper Midwest? (2)

16-17,17-18, and 18-19 are the 1 hour periods when tornadoes occur mostfrequently in the Upper Midwest.

2. Why don’t moretornadoes form in the morning (hint:think about the atmospheric conditions necessary for tornadoformation)? (2)

Theformation of a tornado results from the strength of thunderstormbeing experienced. In most cases, thunderstorms usually gain most oftheir momentum and energy after the heating from solar as well as therelease of latent heat after the water vapor condenses. This happensmostly during the day because of the heating from solar energy duringthe day which is absent in the morning resulting in less tornadoes inthe morning. People should however, not disregard the possibility ofa tornado in the morning.

3. Figure2 shows the average annual number of tornadoes reported in eachstate, with data from 1991 to 2010.

  1. What 3 states experience the most average annual tornadoes? (2)

Thestates experiencing most average annual tornadoes are Texas, NewJersey, and Kansas.

  1. What is the biggest issue with comparing the total number of tornadoes in states like Oklahoma and Texas? (2)

Thebiggest issue with the comparison of total number of tornadoes instates like Oklahoma and Texas is the difference in their sizes.

4. Figure 3 shows the average annual number of tornadoes per 10,000square miles in each state. Reporting tornadoes per land area allowsfor a better comparison of actual tornado frequency and theprobability that you or your land will be hit by a tornado.

  1. Based on this new map, what state has the most tornadoes per 10,000 square miles? (1)

Kansashas the most tornadoes per 10,000 square miles.

  1. If you were going to re-draw “Tornado Alley” based on this map, what states would you exclude or include? (2)

Basedon this map, there is no state I would include or exclude if I wereto re-draw “Tornado Alley”.

5. Figure4 shows the number of tornadoes in Illinois between 1950 and 2011,separated by their Fujita intensity. Using this figure, explain therelationship between tornado intensity and tornado frequency inIllinois. Is it a negative or positive relationship? (3)

Therelationship between tornado intensity and tornado frequency inIllinois is a negative relationship. This is because the more thenumber of tornadoes, the less the frequency.

6. Figure5 shows the number of tornado fatalities in Illinois between 1950 and2011, separated by their Fujita intensity.

  1. Explain the relationship between tornado intensity and fatalities. Is this relationship generally positive, negative, or neutral? (2)

Therelationship between tornado intensity and fatalities is neutral.From the figure, the number of fatalities are not dependent on thetornado intensity. Although there seems to be a positive relationshipat the start, the relationship is broken at EF4 because it has higherfatalities compared to EF5 which has a greater frequency.

  1. The most fatalities in Illinois (100) have occurred with F4 tornadoes, and not F5 tornadoes, why do you think this is the case? (2)

Thestate official could have observed the effect of tornadoes andinitiated strategies to counter the effect of tornadoes throughprograms which reduce its effect once it strikes.

  1. Based on the information presented in Figures 4 and 5, which tornado intensity has the most deaths per tornado (hint: divide the frequency by the number of fatalities)? (2)


TheTri-State Tornado

Youmay have never heard of it, but the Tri-State Tornado was the worst(in terms of deaths) tornado in American history. It’s particularlyrelevant to our area because the majority of deaths (more than 200)occurred in Murphysboro, and the path of the tornado was just northof Carbondale. It is also an infamous event as it still holds therecord for longest recorded tornado path (219 miles!).

Toget a general overview of the storm, examine this entry from US: (follow the link byclicking). This sitehas a lot of great information about the storm and its impact, aswell as answers to Lab questions. Be sure to read “WeatherIngredients” “1925: Now vs Then” and the “First HandAccounts” and look at the photographs.

Thenread the Stormstalkernarrative of thetornado, complete with images of its destruction: answer the following questions about the tri-state tornado.


1. Namethree towns on the track of the tornado. Have you ever lived anywherealong the path of this tornado? (4)

Threetowns on the track of the tornado are Missouri, Illinois, andIndiana. I have never lived anywhere along the path of this tornado.

2. How much warning didthe public have about the tri-state tornado, and how did they receiveit? (4)

Thepublic had little warning about the tristate tornado. The warningthey had was from the events happening hours before the tornadooccurred. They did not receive it with precaution because theyhappened during a time a tornado is not expected and continued withbusiness as usual. This resulted in more deaths and damages whichcould have otherwise been prevented.

3. Isit likely that another tornado this large will occur? If so, is itlikely to cause as many deaths? Why or why not? (8)

Itis likely that another tornado this large will occur. This is becausethe events surrounding the occurrence of the tornado remainmysterious. To begin with, the tornado occurred during morning hourswhich is unlikely time for the occurrence of one especially with suchintensity. Again, the meteorologists had not foreseen it coming toadvice people on how to counter its effects. Basing on the fact thatthe events surrounding the tornado were unpredictable, there is somelikelihood that the same would repeat itself and result in anotherlarge tornado. However, it is not likely to cause as many deathsbecause people can be empowered with information on how to remainsafe and healthy during and after math of a tornado.