Tornadoes and Mobile Homes in the Southeastern United States:
The Geographic Data of a Stereotype

Andrew Shears
Kent State University

An idea often held in the mainstream society in the United States is a phenomenon of common occurrence between tornadoes and mobile home residences.  There are a number of possible explanations as to the origin and continuance of this perception, including the focus of media coverage, a socio-economic bias against those living in mobile homes, or a true coincidence of time and space between mobile homes and tornado events.  The possible existent geographic relationships between these two variables are explored in regionally in the southeastern United States, using data encompassing 1970-2000.

In terms of assessing hazardousness, mobile home residents are extremely vulnerable to tornadic activity.  Dow (1999) defined vulnerability as “the differential susceptibility of ecosystems, households or social groups to losses, expressed as a function of exposure, resistance and resilience.”  Mobile homes residents have a very unfavorable combination of these factors that causes a very high vulnerability to disasters, especially tornadoes.

The ability to withstand the impacts of a hazardous event and continue functioning normally, the resistance of mobile homes against the strong winds of a tornado event is low because of the difference in construction techniques.  In the development of a scale for tornado categorization, Fujita (1971) noted that mobile homes are destroyed by winds as low as approximately 110 miles per hour, the equivalent of the F1 level.  Additionally, Fujita found that permanent site-built frame houses, on the other hand, were damaged by tornado winds between 156-206 miles per hour (F3 level) and destroyed by winds over 207 miles per hour (F4 level).  The results of McDonald and Mehnert (1989), Wakimoto and Black (1994), and Schmidlin et al. (2002) all confirmed that mobile homes are less able to resist the impacts of tornado winds.

While the resistance of mobile homes to strong winds is poor, the ability of the residents to return to full forward momentum after a disaster, called resilience, is nearly non-existent.  Mobile homes residents tend to be less affluent because the price of an average new site-built home is nearly four times that of a new mobile home (U.S. Census Bureau, 2004).  Hurley (2001) noted that the financial situations of mobile homes are similar to automobiles.  Compared to site-built homes, they are unfavorably treated financially as personal property, with mortgages and insurance policies representing those of automobiles.  Also like automobiles, the mobile homes depreciate in value over time, essentially trapping the residents to their mobile homes.  The lack of resources, disappearing capital and unfavorable insurance terms mean that returning to normalcy is far more difficult for mobile home residents.

Exposure, the final factor to calculating the vulnerability of mobile homes, is the least explored.  From an aspatial perspective, lower F-scale tornadoes happen more frequently than stronger tornadoes.  Because less wind speed is necessary to destroy mobile homes, it can be stated that winds capable of destroying mobile homes occur more often.  Belles and Smart (2002) found that regionally, the southeastern United States has a high density of both mobile homes and tornadoes and suggested that this regional coincidence may explain the stereotype.  However, the study lacked spatial resolution sufficient to make further generalizations.

In order to refine this spatial resolution and to search for explanations of the stereotypes of mobile homes and tornadoes, the southeastern United States was chosen for an in-depth study.  A database of historical tornado events was compiled for F2 and above tornadoes in the southeastern United States including 1970-2000.  Densities of tornado events during this period were calculated via an overlay analysis of counties and census tracts.  Housing data from the 2000 United States Census was used to record densities of mobile homes for both county and census tract units.  The densities of the variables in each unit were then compared statistically to explore whether mobile homes, as of 2000, were located in areas that were climatologically prone to tornado events.

Works Cited:

Belles, Jim and Rondah Smart.  2002.  Tornado Risk in the Southeast United States. Presented at the Southeast Severe Storms Symposium, Starkville, MS, February 15- 17, 2002.

Dow, Kirstin.  1999.  The Extraordinary and the Everyday in Explanations in Vulnerability to an Oil Spill.  Geographical Review 89: 75-93.

Fujita, T. T.  1971. Proposed characterization of tornadoes and hurricanes by area and intensity.  Chicago, IL: University of Chicago, SMRP Research Paper 91, 42 pp.

Hurley, Andrew.  2001.  Diners, Bowling Alleys and Trailer Parks: Chasing the American Dream in Postwar Consumer Culture.  New York, NY: Basic Books.  409 pp.

McDonald, James R. and J.F. Mehnart.  1989.  Review of Standard Practice for Wind-Resistant Manufactured Housing.  Journal of Aerospace Engineering 2: 88-96.

Schmidlin, Thomas, Barbara Hammer, Paul King, Yuichi Ono, L. Scott Miller and Gregory Thumann.  2002.  Unsafe at Any (Wind) Speed?: Testing the Stability of Motor Vehicles in Severe Winds.  Bulletin of the American Meteorological Society 1821-1830.

U.S. Census Bureau.  2004.  2000 Census Summary File 3 [online].  Generated by Andrew Shears, using American FactFinder, 2004 [cited 1 October 2004].  Available from the World Wide Web: (http://factfinder.census.gov/).

Wakimoto, Roger M. and Peter G. Black.  1994.  Damage Survey of Hurricane Andrew and its Relationship to the Eyewall.  Bulletin of the American Meteorological Society 75 (1994): 189-200.