Mobile Homes and Weather: Left to the Elements?
University Corporation for Atmospheric Research
In 1890, photographer Jacob Riis's book "How the Other Half Lives" documented the appalling conditions in the tenements that then housed three-quarters of the people of New York City. Riis helped generate public outrage and, eventually, the political will to transform the system that regulated housing in New York and across the nation.
Today, some 21 million U.S. residents – over 7 percent of the public – live in mobile homes (or manufactured homes, as the industry prefers to call them). These homes fill an important niche. Affordable housing is more and more difficult to find in many areas. People who could never afford to purchase a traditional single-family home can build equity in a free-standing structure of their own. The pull of "God's little acre" is a powerful one in America.
Yet, when not heaping scorn on the residents of trailer parks, society at large seems content to ignore them. When was the last time you saw a TV series with a continuing character who lived in a mobile home? Even more disturbing is the willingness of government to overlook the safety of a substantial number of our citizens. Weather poses a risk to mobile home residents in several ways, not all of them obvious. For example, many mobile homes are sited in or near flood plains. In the devastating July 1997 flash flood in Ft. Collins, Colorado, four out of the five residents who died lived in a single mobile home park.
The best-known weather risk for mobile homes is tornadoes, and with good reason. According to the NOAA Storm Prediction Center, out of 829 total tornado fatalities that occurred between 1985 and 1999, 334 (or about 40 percent) occurred in mobile homes. Assume that an average of 6 percent of the U.S. population lived in mobile homes during this period. If all other Americans had died at the same rate as mobile home residents in tornadoes, then the toll for that 15-year period would have been more than 5,500 people. The statistical disparity was even greater in the year 2000, when 29 out of 40 U.S. tornado deaths were linked to mobile homes.
Of course, most people are aware that mobile homes are risky in tornadoes, as evidenced by the pop notion of mobile homes as "tornado magnets." On its Web page, the Manufactured Housing Institute explains the tornado-magnet idea in a puzzling way. The MHI claims that the impression occurs because "manufactured housing is most abundant in rural and suburban areas where meteorological conditions favor the creation of tornadoes."
The MHI adds that "a direct hit from a tornado will bring about severe damage or destruction of any home in its path – site-built or manufactured." Indeed, in an F5 tornado on the Fujita scale (top winds exceeding 260 mph), conventional homes are removed from their foundations. But only about one in a thousand U.S. tornadoes is this strong. About 25 percent are rated F2 or F3 (winds of 113 to 206 mph). Winds at this strength can demolish mobile homes without destroying conventional homes. According to Tom Schmidlin (Kent State University), it appears that even parked autos – which are designed to be aerodynamic and sit closer to the ground – may be safer than mobile homes in tornadoes of this strength. Schmidlin's survey of 180 vehicles struck by tornadoes in 1996 and 1997 found that only 15 percent were tipped over by F3-level wind, and less than half (39%) of the vehicles sustained enough damage to cause serious injury to potential occupants.
Any strategy to reduce the number of fatalities in mobile homes from tornadoes could begin with mobile home parks (or "manufactured housing communities"). The concentration of many homes in a small area hikes the risk for a major tornado disaster. Slightly less than half of all mobile homes are sited in such parks. Nobody knows how many of the parks have shelters. Minnesota now requires shelters to be built in new mobile home parks, but such requirements are virtually absent in other states. A soon-to-be-published survey by Schmidlin indicates that a high percentage of parks in the Great Plains have shelters of some sort, while most of those in the Deep South don't. Yet a disproportionate number of tornado deaths overall occur in the South, in part because tornadoes there are more likely than in other regions to strike at night.
Other questions abound: Are shelters always accessible by residents, or are they locked at critical times? How many people can comfortably fit in a shelter for an hour or so? How many shelters are recreation centers or other multi-use structures unsuited to stand up to a tornado? And how often do people actually use these shelters? In the catastrophic May 1999 tornado that struck the south Oklahoma City suburbs, my sister-in-law and nephew drove a few blocks to take shelter at his school rather than going to their mobile home park's shelter. The tornado missed their home by three blocks but struck the upper part of the school, leaving them uninjured but rattled.
In March the U.S. House overwhelmingly voted to make mobile home parks eligible for Community Development Block Grants for building tornado shelters. Under current law, site-built homes, schools, and apartment buildings have been eligible for such grants, but not mobile homes (another sign of their residents' political invisibility). The bill has yet to be considered in the Senate. Its passage would be a step in a much-needed direction, although it still falls short of mandating shelters – something that in other contexts might be considered a matter of basic public safety.
This is only part of the equation, though. Millions of mobile homes are sited on private lots, largely in rural areas. Their owners may not have any suitable shelter for miles around. Current safety practices encourage them to take shelter in a ditch. However, as Schmidlin has noted, ditches are not exactly an inviting haven. Floods can rush through, snakes and other animals may pose a threat, and trees and power lines can crash down. If in fact taking shelter in a parked car is the safest nearby option for residents of isolated mobile homes, this message – counterintuitive as it is – could be put to work saving lives.
Aside from the congressional action, there are other encouraging signs. The MHI launched an initiative in 1999 to offer NOAA weather radios at a 50 percent discount to people who live in MHI-affiliated communities. However, a tornado warning does little good unless people know how best to respond. Information is critical, and the public (including mobile home residents) is often poorly served. For instance, the U.S. Housing and Urban Development department strengthened its standards for mobile home construction in coastal areas following the massive destruction of Hurricane Andrew in 1992. Several news stories since then have inaccurately stated that new mobile homes across Tornado Alley are built to withstand 100-mph winds. In fact, the upgrade to that level was limited to Florida and to a strip just inland of the Gulf and East Coasts. In the Plains and Midwest, the federal standard remains as it has for decades: 60 to 75 mph.
Whether clustered in communities or dispersed in rural America, mobile homes remain out of sight for a large part of the public – and certainly for many policy makers. Time will tell whether we learn to see their weather-vulnerable residents as "the other half" who deserve safe shelter from storms as much as the rest of us.
– Robert Henson
Writer/editor, UCAR Communications
University Corporation for Atmospheric Research
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