She died in her bed.
Brittany May, 17, was asleep at 2 a.m. in Lady Lake, Fla., on Feb. 2, 2007, when a monstrous tornado blew a tree onto her family's mobile home and killed her.
"I've never had to bury a child," her stepmother, Lisa May, said. "I'm going to speak for her mother, and me and her father: This is the hardest thing that any of us will have to do."
Brittany was one of 21 victims of a savage tornado outbreak that slashed across central Florida that month. Tragically, she was in an unusually vulnerable situation: She lived in a mobile home in the Southeast, during a nighttime tornado outbreak in February. That's the deadliest time and place for twisters, according to Economic and Societal Impacts of Tornadoes, a book just published by the American Meteorological Society.
The USA is heading into the prime months for tornadoes, according to the National Weather Service. The private forecasting firm AccuWeather warns that this spring's tornado season will be more active than normal. AccuWeather meteorologist Paul Pastelok says areas of greatest concern lie from Arkansas and Missouri into Tennessee and Kentucky.
"People are 10 times more likely to die in a mobile home than if the same tornado hit a regular home," says book co-author Kevin Simmons, an economist at Austin College in Sherman, Texas.
Simmons says mobile homes constitute only 7% of the USA's housing stock, but his research found that 43% of all tornado deaths are to people in mobile homes, which can be no match for a tornado's violent winds, clocked as high as 300 mph.
Simmons and co-author Daniel Sutter of the University of Texas-Pan American in Edinburg became interested in tornadoes in 1999, when, living in Oklahoma, they both witnessed one of the most devastating in U.S. history: the May 3 Moore, Okla., twister that killed dozens of people and cost $1.1 billion in damage, according to the Storm Prediction Center.
Such storms are not just about economic damage and resilience by affected communities; they raise a myriad of related issues, such as the effectiveness of Doppler radar, the impact of false alarms and which protective structures are most cost-effective.
The National Weather Service reports that tornadoes kill 56 Americans each year, based on the average from 2000-09, the most recent years for which data are available. This makes tornadoes the fourth-deadliest weather hazard in the USA, after heat, hurricanes and floods.
Roughly 1,200 tornadoes touch down in the USA every year. Other findings from the book:
• The widespread installation of Doppler radar in 1992 "reduced fatalities by almost 40%, and injuries by a similar number," the authors write. "When you consider the value of the avoided fatalities and injuries, the value is over $3 billion. The capital cost to install the radar was less than $2 billion, so this is an investment that was well worth the cost."
• Underground tornado shelters and safe rooms can further reduce casualties beyond that achieved through improved warnings, the authors report. The question of whether people should purchase a shelter is ultimately a personal decision depending on how individuals value safety, they say.
"Our analysis finds that the cost per life that can be expected to be saved with shelters is rather high for permanent homes, even in the most tornado-prone states," Simmons and Sutter write.