Upgrades are relatively inexpensive because most of the work comes from adding stronger wall-to-ceiling and wall-to-foundation connections—more nails and hurricane brackets. "You have a lot of reserve strength that isn't being used because of poor connections," which only engage 15%-20% of the strength of the wall, says IBHS's Reinhold.

The problem isn't only cost. Most builders and tradeworkers don't use the right techniques, says Bill Coulbourne, director of Wind and Flood Hazard Mitigation at the Applied Technology Council, Rehoboth Beach, Del.

The $350-million Mercy Hospital Joplin—a 900,000-sq-ft replacement for the city's tornado- ravaged St. John's Regional Medical Center set to open next March—might have benefited from tornado- resistant design criteria. John Farnen, executive director, Mercy Strategic Projects, Chesterfield, Mo. Mercy researched $60 million worth of hardening measures, implementing $12 million, mostly based on hurricane hardening, which added 3% to the cost.

Owners such as Mercy Hospital and communities like Webb City may be raising tornado defenses, but the challenges remain many, says NSSA's Kiesling, who developed the concept of an above-ground storm shelter in 1974.

"Even if we do heroic things in [model] codes for new construction, it will take a long time to make a difference," he says. "We have a quick-fix, short-term perspective as a society, and that's going to blow up in our faces, I'm afraid."