|From Fox News, Smithville, MS|
Here is an illustration: the Smithville, MS tornado (above) has been rated EF-5. This tornado was so strong it pulled up the pavement and tore out a culvert. This type of damage is extremely rare. Maybe one tornado in 1,000 reaches this destructive power. When you are dealing with tornadoes of this violence, there are very few places that offer adequate shelter (i.e., even a basement would be unsafe), thus the extremely high death toll. As far as I am able to determine (again with the caveat that the studies are nowhere near complete) the forecasts and warnings were very good.