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Impacts and Evaluation
DEATHS and DAMAGE FROM SEVERE WEATHER:
Details on the calculation of relative threat of tornadoes to mobile home residents (Updated to complete 2005 data)
Harold E. Brooks,
NOAA/National Severe Storms Laboratory
The National Weather Service has collected data on tornado deaths since the early 1950s. In 1975, they began to track deaths specifically in mobile homes and in a variety of other locations in 1985. The data from 1985-2003 and for subsequent years are available online. Earlier data were published in the Department of Commerce publication Storm Data. The annual totals are given below:
| YEAR | ANNUAL TOTAL |
MOBILE HOME |
PERMANENT HOME |
|---|---|---|---|
| 1975 | 60 | 13 | |
| 1976 | 44 | 18 | |
| 1977 | 43 | 7 | |
| 1978 | 53 | 15 | |
| 1979 | 84 | 9 | |
| 1980 | 28 | 11 | |
| 1981 | 24 | 14 | |
| 1982 | 64 | 20 | |
| 1983 | 34 | 20 | |
| 1984 | 122 | 43 | |
| 1985 | 94 | 28 | 40 |
| 1986 | 15 | 7 | 3 |
| 1987 | 59 | 24 | 7 |
| 1988 | 32 | 21 | 6 |
| 1989 | 48 | 12 | 8 |
| 1990 | 53 | 7 | 25 |
| 1991 | 39 | 23 | 3 |
| 1992 | 39 | 21 | 12 |
| 1993 | 33 | 13 | 6 |
| 1994 | 68 | 24 | 12 |
| 1995 | 30 | 8 | 15 |
| 1996 | 25 | 14 | 8 |
| 1997 | 67 | 28 | 21 |
| 1998 | 132 | 64 | 46 |
| 1999 | 94 | 36 | 39 |
| 2000 | 40 | 29 | 4 |
| 2001 | 40 | 17 | 15 |
| 2002 | 55 | 32 | 15 |
| 2003 | 54 | 25 | 24 |
| 2004 | 36 | 11 | 21 |
| 2005 | 39 | 34 | 3 |
The change in fraction of deaths in mobile homes can be calculated easily from these data.
Online data on housing units in the US come from the Decennial Census of Housing, providing numbers of mobile homes on a state-by-state basis since 1950. To get annual values, I linearly interpolated between the decennial values. In order to calculate the rate of death per resident, I assumed that the mean number of mobile home residents per housing unit is the same as the mean number of permanent home residents. Using that on the national values, the number of deaths per year per million mobile home residents from 1996-2005 was 1.36. For permanent home residents, it was 0.075, a ratio of 17.99:1. Using the data from 1985-2005, the values were 1.17 and 0.064 per million, for a ratio of 18.20:1. Including state-by-state information and interannual variability gives an approximate range on the ratio of 15-20:1.
