The only guaranteed way to avoid becoming a casualty of a disaster is to be somewhere else when it strikes.

Such a mentality is easy to apply to disasters with advanced warning, such as a hurricane. But mass shootings don’t fit into that category.

The horrific school shooting last December in Newtown, Conn., that killed 20 children and six adults, took place six months after a gunman in Aurora, Colo., killed 12 and wounded 58 at a late-night screening of “The Dark Knight Rises,” and a white supremacist killed six and wounded four at a Sikh temple in Racine, Wis.