Tim Marshall
Tim Marshall was born in 1956 in Evergreen Park, IL and experienced his first tornado on April 21, 1967 while living in Oak Lawn, IL. Since then, Tim has studied wind effects on buildings and structures taking part in more than one hundred damage surveys. He works for Haag Engineering Company, a forensic engineering firm, based in Flower Mound, TX.
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This paper summarizes the findings from our damage survey, herein called the Nashville tornado. The authors spent several days traveling the damage path and documented the degree of damage (DoD) to specific damage indicators (DIs) using the EF damage scale (WERC, 2006). The EF-scale was adopted by the National Weather Service (NWS) in 2007.
damage and wind speed. These limitations have led to inconsistent ratings of tornado damage and, in some cases, overestimates of tornado wind speeds. Thus, there is a need to revisit the concept of the Fujita Scale and to improve and eliminate some of the limitations.
Recognizing the need to address these limitations, Texas Tech University (TTU) Wind Science and Engineering (WISE) Center personnel proposed a project to examine the limitations, revise or enhance the Fujita Scale, and attempt to gain a consensus
from the meteorological and engineering communities. A steering committee first was
organized to initiate the project. The next step involved assembling a forum of users to identify the issues and develop strategies to improve the Fujita scale. A panel of wind damage experts met and assigned failure wind speed values to various degrees of damage (DOD) to buildings and other objects. Through this expert elicitation process, wind speeds corresponding to the DOD's were estimated. These estimated wind speeds then determined the EF (Enhanced Fujita)-scale category appropriate for the
observed damage. This paper discusses the work to date in finalizing the EF-scale.
occurred in the southern U.S. with more than 70
tornadoes reported. The worst hit areas were
northeast Arkansas, western Tennessee, western
Kentucky, and southern Illinois. This paper will
concentrate on the damage in western Kentucky,
particularly the towns of Mayfield and Dawson
Springs where the most severe damage occurred.
A detailed damage survey was conducted in the
days following this event and the National
Weather Service rated this tornado EF 4 on the
Enhanced Fujita (EF) Scale. Various degrees of
damage (DoD) were assigned to different damage
indicators (DIs) in accordance with the 2006 EF-scale
(WERC, 2006).
southeast Jonesboro and traveled northeast
through the city damaging about 300 buildings.
There were 22 injuries but
fortunately, no fatalities, which is remarkable
given that the tornado traveled through a densely
populated area on Saturday afternoon. The next day, the authors surveyed the damage
assigning degrees of damage (DoD) to multiple
damage indicators (DIs) in accordance with the
Enhanced Fujita (EF) scale (WSEC, 2006). The
EF-Scale was written in 2006 and adopted by the
National Weather Service (NWS) in 2007. In this
event, NWS personnel plotted the damage
locations on the damage assessment toolkit (DAT)
and assigned a maximum damage rating of EF 3
to this tornado.
This standard will include much more descriptive information than in the original EF-Scale, including more DoDs, more DIs, a narrative describing various resistance levels of each DI, commentaries for each DI, additional guidance photographs, and references to damage surveys including those many of those conducted during the past 15 years. More than 80 scientists from various disciplines have volunteered their time to develop this standard. Thousands of hours have been put into this effort and it is anticipated the standard will be published within the decade. Public input will be requested through a public comment period once the draft standard has completed the committee balloting process – the objective of this paper is to provide an early public view of the proposed changes and process.
This paper summarizes the findings from our damage survey, herein called the Nashville tornado. The authors spent several days traveling the damage path and documented the degree of damage (DoD) to specific damage indicators (DIs) using the EF damage scale (WERC, 2006). The EF-scale was adopted by the National Weather Service (NWS) in 2007.
damage and wind speed. These limitations have led to inconsistent ratings of tornado damage and, in some cases, overestimates of tornado wind speeds. Thus, there is a need to revisit the concept of the Fujita Scale and to improve and eliminate some of the limitations.
Recognizing the need to address these limitations, Texas Tech University (TTU) Wind Science and Engineering (WISE) Center personnel proposed a project to examine the limitations, revise or enhance the Fujita Scale, and attempt to gain a consensus
from the meteorological and engineering communities. A steering committee first was
organized to initiate the project. The next step involved assembling a forum of users to identify the issues and develop strategies to improve the Fujita scale. A panel of wind damage experts met and assigned failure wind speed values to various degrees of damage (DOD) to buildings and other objects. Through this expert elicitation process, wind speeds corresponding to the DOD's were estimated. These estimated wind speeds then determined the EF (Enhanced Fujita)-scale category appropriate for the
observed damage. This paper discusses the work to date in finalizing the EF-scale.
occurred in the southern U.S. with more than 70
tornadoes reported. The worst hit areas were
northeast Arkansas, western Tennessee, western
Kentucky, and southern Illinois. This paper will
concentrate on the damage in western Kentucky,
particularly the towns of Mayfield and Dawson
Springs where the most severe damage occurred.
A detailed damage survey was conducted in the
days following this event and the National
Weather Service rated this tornado EF 4 on the
Enhanced Fujita (EF) Scale. Various degrees of
damage (DoD) were assigned to different damage
indicators (DIs) in accordance with the 2006 EF-scale
(WERC, 2006).
southeast Jonesboro and traveled northeast
through the city damaging about 300 buildings.
There were 22 injuries but
fortunately, no fatalities, which is remarkable
given that the tornado traveled through a densely
populated area on Saturday afternoon. The next day, the authors surveyed the damage
assigning degrees of damage (DoD) to multiple
damage indicators (DIs) in accordance with the
Enhanced Fujita (EF) scale (WSEC, 2006). The
EF-Scale was written in 2006 and adopted by the
National Weather Service (NWS) in 2007. In this
event, NWS personnel plotted the damage
locations on the damage assessment toolkit (DAT)
and assigned a maximum damage rating of EF 3
to this tornado.
This standard will include much more descriptive information than in the original EF-Scale, including more DoDs, more DIs, a narrative describing various resistance levels of each DI, commentaries for each DI, additional guidance photographs, and references to damage surveys including those many of those conducted during the past 15 years. More than 80 scientists from various disciplines have volunteered their time to develop this standard. Thousands of hours have been put into this effort and it is anticipated the standard will be published within the decade. Public input will be requested through a public comment period once the draft standard has completed the committee balloting process – the objective of this paper is to provide an early public view of the proposed changes and process.