Visualization of Tornado Data Anu Joy, Harshal Chheda, James Chy and Yuxing Sun Drexel University ABSTRACT— The aim of this project is to study the nature of tornadoes with the use of information visualization tools. The emphasis of this project is to study the tornadoes that change directions and their effects. For this report we used a subset of published storm data from the National Oceanographic and Atmospheric Administration (NOAA). The data set included many types of storms, but we focused upon just the storm data relating to tornadoes. Both Tableau and IBM Many Eyes were used as the information visualization tools to perform graphical analysis of the data. When visualizing the data, we focused on the BEGIN_AZIMUTH and the END_AZIMUTH parameters in the data, which reflect the change of tornado directions. We found that tornadoes do frequently change direction. Tornadoes that probably went straight seemed to have much less in injuries than ones, which probably changed course. We had difficulties using the visualization tools convey any aggregated information regarding directions in general because the direction was not presented as numeric values in NOAA data. During the preparation of visualizations, we found some skills to change and improve the presentation of data. improved in step with advances in technology, most prominently 1 INTRODUCTION with increasingly more sophisticated radar systems. Numerical simulations continue to improve with increased computer power, 1.1 Brief History of Tornado Research speed, and storage capabilities. Researchers continue to be fascinated by tornadoes and measure 1.2 Brief History of Research into Tornado Path and observe the paths tornadoes follow, the months they are Research occur, and regions in which are tornado prone. Researchers exploring tornado mysteries examine tornadoes from different Most research suggests that Tornado paths range from 100 yards viewpoints such as the following: genesis, dynamics, detection, to 2.6 miles wide and are rarely more than 15 miles long, although warning decision support, forecasting, preparedness and some strong tornadoes on record have crossed through multiple climatology. Tornado research targets ways to improve forecasts states (e.g. the Tri-State Tornado of 1925). Tornadoes can last and warnings in order to help save lives. Officials documented the from several seconds to more than an hour. However, most don't first observation of tornadic storms in 1953 in Illinois (9 April) exceed 10 minutes. Most tornadoes travel from the southwest to and Massachusetts (9 June 1953) by radar at the Illinois State northeast with an average speed of 30 mph, but the speed has been Water Survey and the Massachusetts Institute of Technology observed to range from almost no motion to 70 mph. Also the (MIT), respectively. Stuart Bigler made other similar observations timeframe for tornadoes occur in the Deep South and in the broad, at Texas A&M University. These early observations showed that relatively flat basin between the Rockies and the Appalachians, hook echoes are related to tornadoes. From the late 1950s but no state is immune. Peak months of tornado activity in the onward, and especially in the 1960s and 1970s, a Tornado U.S. are April, May, and June. However, tornadoes have occurred researcher at the University of Chicago named, Ted Fujita, made in every month and at all times of the day or night. A typical time painstaking analyses of tornado damage, tornado photographs. He of occurrence is on an unseasonably warm and sultry spring integrated these analyses with “mesoanalysis” of surface data. afternoon between 3 p.m. and 9 p.m. Based on photographs of a Fargo, ND tornado in June 1957, he described tornadoes using terminology such as “wall cloud” and Emergency service personnel notify the public of a tornado in “tail cloud.” Because of his work many of these terms persist their area through many channels. In a survey of an Oklahoma today. He also categorized tornadoes on a scale based upon wind City tornado on May 3rd, 1999, survivors indicated they took speed estimates and inflicted damage. Researchers later named safety precautions when they heard the tornado warning on this scale the “Fujita Scale” in his honor. The lowest tornado on television, a telephone call, warning sirens, or from AM/FM the scale was an F0 and progressed in strength to F5. In 2007, the radio. Weather band radios were another source, but few of those NOAA data officially switched to an enhanced Fujita scale to survivors indicated a weather band radio provided their first improve the precision of the scale. In 2007 and later, the warning notice. Many survivors received the warning from tornadoes ranged from EF0 to EF5 where EF indicates the multiple sources. Those with injuries stayed in their homes after “Enhanced Fujita” scale. After viewing tornado damage from receiving the warning. The survivors without injuries left their aircraft, he documented cycloidal ground marks and associated home to enter a personal or public storm shelter [9]. Other them with multiple-vortex tornadoes. On the basis of aircraft researchers of that same outbreak indicated that relatively flights over a tornadic storm in 1977 he suggested that inexpensive structural improvements could greatly improve safety thunderstorm downdrafts generate tornadoes. to those taking shelter in their homes or in other buildings [4] We unable to find any documentation indicating that emergency The history of tornado research consists of a series of both services notified people based upon the direction the tornado was serendipitous and planned observations and measurements, heading at the time it first touched down. The direction a tornado numerical studies with idealized models, laboratory-vortex around Kellyville, Texas, on June 8th, 1995 had not only a distinct experiments, and numerical simulations. Observations have cusp in its path, but also followed a sine-like wave during a portion of its travel [15]. Researchers also identified unusual with its path. A table below the map shows a summary of the damage tornado paths as they alternate side-to-side within a tornado injuries, fatalities, longest path and the widest path for mesocyclonic region, a large band encompassing the parent storm each tornado. While the visualization provides a method to view during a rare Massachusetts tornado on May 29rd, 1995 [14]. each individual tornado, it does not provide any mechanism to compare data between various tornadoes. 1.3 Brief History of Research into Predicting Tornado Path An interesting visualization in Tableau created by Alex Kerin [22] showed a very detailed multiple visualizations of Tornado data Studies have found that tornadoes usually travel at the same speed from NOAA, superimposed on state area and population data. A and in the same direction as their parent thunderstorms. In a number of tabs display various tornado data visualizations from pioneering research paper published in 1987, Dr. Tetsuya Fujita different perspectives. Each section of the visualization has filters (1920-1998), the severe weather researcher, categorized the that can be applied to zero in on a specific piece of information. known direction of 17,081 tornadoes in the U.S. for the period 1916-1985. He found that 59 percent of those tornadoes traveled A New York Times tornado map [6] from 2011 portrayed tornado from the southwest; 19 percent from the west; 11 percent from the path and showed tornado deaths by county, spread over the years northwest; 6 percent from the south; 2 percent from the southeast; 1950-2011. The number of deaths associated with the tornado was and 1 percent each from the east, north and northeast. depicted with the help of circles. The visualization showed 2011 as one of the deadliest year for tornadoes. 1.4 Research into Predicting when a Tornado might change its path Another New York Times visualization [5] mapped the number of tornadoes each hour between the time periods of April 21 to April Two studies about tornadoes, which changed directions, made 28 on the map of US. The map is motion animated and depicts the some interesting points in predicting when a tornado might distribution of tornadoes over the given time period. The map uses change its path. color to depict the number of tornadoes. One is about the tornado occurred on 5/15/2013 in Granbury, TX 1.6 Existing Visualization of Tornadoes changing [23]. The tornado was a strong one, rated as EF-3. At first, it direction moved along southeaster but later turned about 110 degree left to due north. TX tornado was compared to a Greensburg, KS Data visualization expert John Nelson created two visualizations tornado, which also turned its path to, left and did a full 360- associated to paths and directions of tornadoes. The first one degree. The study indicated that both tornadoes experienced a termed ‘Tornado Travel Map’ showed a breakout of the directions “mesocyclone core evolution”: When the cold air from the rear in which tornadoes traveled over the last 63 years. The idea flank downdraft wrapped around the tornado completely, it behind this visualization was driven by the prospect of the average stopped the warm air coming into the tornado. Then the tornado tornado bearing as input to divide the country into tornado occluded and turned left, and a new mesocyclone would warning zones. He used the compass to provide an overall regenerate to its southeast. The study pointed out that it appears a reference of tornado travel in the visualization. The data was tornado turns left only when it decays rapidly. extracted from the archived tornado data available in the NOAA/NWS Storm Prediction Center sites. The most significant The second study is about a tornado in El Reno, Oklahoma on insight provided by this visualization was that most storms tend to 5/31/2013, which had a weak speed wind in the middle level [8].