Lab 2 Tornadoes 2023

Geology 116, Fall 2023 Name __________________ Lab 2 Tornadoes You can find a lot of information about tornadoes on the Online Tornado FAQ Page . We’ll be using a number of links from the page, but feel free to explore more! Section 1: Tornado Scale The intensity of tornadoes is generally measured in the U.S. using the Enhanced Fujita damage scale ( http://www.spc.noaa.gov/efscale/ ). This is modified from a less quantitatively based scale devised in 1971 by Dr. T. Theodore Fujita; the enhanced scale provides more accurate values of the wind speeds associated with different levels of damage. Tornadoes often occur in outbreaks, with multiple tornadoes being produced along one frontal boundary, sometimes close in both space and time. One of the highest number of tornadoes in an outbreak occurred when 412 tornadoes touched down between May 1 and 10, 2003. One of the hardest hit areas was near Pierce City, Missouri. 1) Use the links below and the storm path map and photos of damage to try estimating damage yourself based on the Enhanced Fujita damage scale. 2) Watch the video that shows examples of damage at various EF levels: . 3) Review the EF-scale, including the general criteria and damage results, as well as the illustrations below.

Damage at different EF levels, Greenburg KS tornado 4) Based on the descriptions and photos for these different levels of tornadoes, estimate the EF-scale number and description of damage for the photos from the May 4 2003 tornado outbreak in Missouri that are shown on the next page. City EF Estimate Wind Speed Est. Description of Damage Pierce City, MO Clever, MO Battlefield, MO 5) Find information from internet sources about the effects of the tornado at the three locations listed on the next page. What was the full extent of damage? There were multiple tornadoes during the outbreak in the region. How did this tornado compare with others in the outbreak?

2. Which season(s) has/have the most frequent tornadoes? 3. How does the location of the most frequent tornadoes shift during the year? Do the data support the hypothesis described above? 4. Florida is also a tornado “hot spot”. When are tornadoes most frequent there? Why? The frequency of tornadoes also varies year to year, as shown in the maps here . Is there any correlation between the frequency of tornadoes and the impacts of El Niño and La Niña events in the Pacific? Construct a table or spreadsheet with: (a) whether tornado occurrence in the year was relatively low, medium, or high; (b) the geographic distribution of tornado frequency for each year -- greater concentration of tornadoes in the north, central, or southern third of the country; (c) column showing if the year had an El Niño or La Niña event. 1. What criteria did you use to characterize the relative frequency of tornadoes? 2. What states/areas do you describe as north, central, or south? 3. Do years of high tornado frequency correlate with either El Niño or La Niña events (see table on next page)? With strong or weak events? What about years of low tornado frequency? 4. Does the distribution of tornadoes correlate with either strong El Niño or La Niña events? In other words, do years of greater concentration of tornadoes in the south correlate with strong or weak El Niño or La Niña years? What about years when tornadoes are more concentrated in the north or center? 5. What conclusion, if any, can you draw about the relationship between El Niño and La Niña and the frequency and distribution of tornadoes? El Niño La Niña Weak - 12 Moderate - 7 Strong - 5 Very Strong - 3 Weak - 10 Moderate - 5 Strong - 7 1952-53 1951-52 1957-58 1982-83 1954-55 1955-56 1973-74 1953-54 1963-64 1965-66 1997-98 1964-65 1970-71 1975-76 1958-59 1968-69 1972-73 2015-16 1971-72 1995-96 1988-89 1969-70 1986-87 1987-88 1974-75 2011-12 1998-99 1976-77 1994-95 1991-92* 1983-84 2017-18 1999-00 1977-78 2002-03 1984-85 2007-08 1979-80 2009-10 2000-01 2010-11 2004-05 2005-06 2006-07 2008-09 2014-15 2016-17 2018-19 2019-20