The latter thought is said to be a myth. Or so we have been told.
As general sources like Wikipedia note, the idea that manufactured housing units, or mobile homes/trailers, attract tornadoes has been around for decades. This may appear to be true at first from looking at tornado fatality statistics: from 2000 to 2008, 539 people were killed by tornadoes in the US, with more than half (282) of those deaths in mobile homes. Only around 6.8% of homes in the US are "manufactured/mobile homes."
The skeptics say that it is highly unlikely that single-story structures such as mobile homes can have a substantial effect on tornado development or evolution. More people are killed in trailer parks because mobile homes are less able to withstand high winds than permanent structures, the debunkers remark. Winds which can demolish or roll a mobile home may only cause roof damage to a typical one- or two-family permanent residence. Another likely contributing factor to the continued propagation of this myth is confirmation bias: whenever a new instance of a tornado hitting a mobile home park occurs, media outlets report on it more extensively, ignoring damage to the surrounding area which may not have produced as many casualties, this according to Thomas P. Grazulis (2001: p. 12), "Tornado Myths" in The Tornado: Nature's Ultimate Windstorm. University of Oklahoma Press.
But among Forteans, tornadoes and trailers (a/k/a mobile homes) have been openly discussed since the 1970s.
Now comes confirmation that the "myth" may not be a folktale, after all, and the Forteans were correct.
The study, entitled "Land-surface Heterogeneity Signature in Tornado Climatology? An Illustrative Analysis over Indiana 1950-2012," appeared on December 2, 2013, in Earth Interactions, a journal published by the American Metrological Society.
Researchers at an important research university think they have pinpointed areas where tornadoes are more likely to hit, said press accounts.
Researchers looked at 60 years worth of climatological data from the National Weather Service’s Storm Prediction Center, and found tornadoes touch down most often in “transition zones” – areas where a dramatic change in landscape takes place. In other words, where tall buildings end and farmlands begin, or where a forest stops and the plains start.
Indiana state climatologist Dev Niyogi, who co-authored the study, said the data might explain why mobile home parks are often called tornado magnets, as they are typically located just outside city limits in open fields.
“That essentially goes to the heart of it,” he said. “How do we make settlements or landscape more resilient, and clearly there might be ways that we can make our livelihoods and lives safer.”
The study found tornado touchdowns in urban areas occur approximately 1 to 10 miles from the city center.
“From an average person’s perspective, what the study looks into is what the future cities would look like, in terms of trying to avoid larger high-impact weather,” Niyogi said.
He said city planners might need to pay closer attention to the so-called transition zones when laying out large-scale construction plans in the future.
In an effort to better grasp where exactly tornadoes tend to touch down, the researchers concluded that twisters have a statistical preference for causing the most damage in so-called “transition zones” — geographic areas where two distinct types of landscapes meet and dramatically change. Examples include the fringe areas that fall between built-up suburban sprawl and rural farmland, dense forests and rolling plains. More often than not, these sparsely developed, lowly populated outskirts are where mobile home communities can be found in the greatest numbers.
According to the team's findings, between 1950 and 2012, 61 percent of tornado touchdowns in Indiana occurred within 1 kilometer of built-up urban areas. Forty-three percent of twisters touchdowns fell within a kilometer of heavily forested areas. In other words, primo areas for mobile home settlements.
This is not to say that tornadoes never strike cities and heavily populated urban centers (on occasion, they do) and that trailer parks are always located in transition zones. But the trend does shed light on why when many tornadoes strike, a trailer park or two on the far edge of town always seems to get hit and hit badly (the severity of damage has more to do with the construction of mobile homes and the fact they aren't anchored to the ground than geographic locale).
What university site would we find this research being conducted? In correspondence with Jim Brandon about this, he would write me:
What made me chuckle, though, is the little name game played on these explaining academics. Purdue (Fr. perdue = “lost”) University is located where? Why, West Lafayette, Indiana, of course.That's right. The study occurred at Purdue University, Indiana State Climate Office, Purdue University, West Lafayette, Indiana.
An ithyphallic (“with erect penis”) Pan pursues a shepherd. Behind Pan the ithyphallic herm refers to Pan’s parentage from Hermes, and also to the rural setting. Red-figured vase, c. 470 BC, Museum of Fine Arts, Boston.