In response to my distress at New York City’s promise to protect us from Saturday’s blizzard, Gregg Nelson writes, I often watch and enjoy National Geographic’s “Seconds From Disaster” documentaries on Youtube. Each one starts with the narrator saying, “Disasters don’t just happen. They’re a chain of critical events.” When I read Nanny Bloomberg’s storm warnings I think they should be preceded by a narrator saying, “Disasters don’t just happen. They’re the result of deliberate government policies.”