Plaza Towers Elementary School in Moore, Okla., is pictured from a National Guard helicopter during a tour of tornado damaged areas (AP Photo/Sue Ogrocki)

Numerous children were killed or injured by the tornado that obliterated Plaza Towers Elementary School in Moore, Okla. Details are still emerging about exactly how these casualties occurred, but the tragedy raises questions about what schools should do to protect their students during tornado situations.

In most circumstances, children will be safe in sturdy, interior rooms (away from windows) on the ground floor during a tornado – like hallways or bathrooms. But when the most violent tornadoes strike, rated EF4 or EF5 on the 0-5 Enhanced Fujita Scale – with winds up to 200 mph or even higher, no place above ground is safe.

Rob White, a meteorologist who runs The Original Weather Blog, was at a loss for an appropriate solution per comments on his Facebook page:

There is no easy answer. In some states, especially in the Deep South, they cancel school when a major severe weather day is forecast. I have mixed feelings about that too, because often times it means leaving kids in a mobile home or other undesirable structure during a tornado – in which case they would have a much better chance surviving at school. But like I said before, in an EF-4 or EF-5, you’re not safe unless you’re under ground. It’s that simple.

So what do we do, put underground shelters in schools in “tornado alley”? Or just keep rolling the dice.

It would be extraordinarily expensive to mandate schools build underground shelters large enough to house an entire school’s population in tornado-prone areas.

And White is right that if schools are closed, some students may be less safe at their homes should they be poorly constructed and/or lack underground shelter. But perhaps closing school is a less risky strategy since the students would be dispersed rather than all in one place.

Then, you have to consider the price of a missed day of school. While you could reasonably decide to close schools on those rare days each year when the National Weather Service determines there is an elevated tornado risk, most locations statistically will not get hit by life-threatening weather on those days.

I don’t pretend to have the answers to this question. It’s a challenging risk management problem. But it’s a topic worthy of discussion and I welcome your thoughts.

Update: The NY Times’ Andrew Revkin has some insights on schools, tornadoes and building standards in his post: A Survival Plan for America’s Tornado Danger Zone