A 7-year-old British girl died last week when a gust of wind lofted a "Toy Story" bouncy castle into the air before it fell back down nearly a mile away. The incident, which occurred at a fairgrounds 30 miles north of London, reveals the often-overlooked danger of large, inflatable outdoor play spaces in the wind.
John Knox, an atmospheric science professor at the University of Georgia, has been actively investigating this problem and documented 64 bounce house accidents due to wind worldwide since 2000. These accidents have caused 271 injuries and 10 deaths, he says.
Knox says wind gusts of 20 to 30 mph can dislodge these structures if they are poorly secured. The accidents typically occur away from big storms, when strong gusts seemingly come out of the blue.
"These are all cases that seem like nice weather, but then all of the sudden you can have trouble," Knox says.
These difficult-to-anticipate gusts often occur during the afternoon after the passage of a cold front or from the outflow from thunderstorms, potentially many miles away from the parent storm, Knox says. He has also seen cases in which very small whirlwinds such as dust devils and waterspouts have spun up on otherwise fair weather days and lifted up bounce structures.
The gust of wind blamed for the accident in the United Kingdom last week was described as "sudden."
"Had it been a consistent wind they would have closed down all the inflatables," Ray Smith, a representative of the Showmen's Guild of Great Britain, told the BBC.
Although Knox is unaware of the regulatory environment overseas, he says better regulations could prevent accidents of this kind in the United States.
"There has been very uneven regulation of inflatable amusement devices from one state to another in the U.S.," he says. "Some states [for example, North Carolina] specify policies for anchorage of bounce houses, operator requirements, owner requirements, signage, wind speed thresholds for use, a renter clause, and so on. Other states do not have policies."
In the United Kingdom, a man and woman, employees of the fair where the 7-year-old died, have been arrested "on suspicion of manslaughter by gross negligence," the BBC reports.
Knox says that assigning blame in these cases is "very complicated" but that his research group is "emphasizing better education regarding the risks that bounce houses pose, particularly in windy weather."
Last summer, Knox led a class in which students set up a bounce house and tested different anchoring techniques, one with stakes and one with sandbags, to see how they handled the stress. He is working on an academic paper based on the results.
Wind is just one potential hazard when children play in bounce houses. Injury rates in inflatable amusement devices from all causes increased 15-fold from 1995 to 2010 in the United States, according to a study published in the journal Pediatrics in 2012. Nearly 65,000 injuries were reported in the study period — roughly one every 46 minutes. Most of the injuries were broken bones, strains, and sprains from jumping and falls inside the bounce structures.