By the time Sandy came ashore near Atlantic City, N.J., on Oct. 29, it was no longer a hurricane: The National Weather Service had reclassified it as a post-tropical cyclone. Yet a storm by any other name is just as harsh, and the floods, winds, property destruction, power outages, gas shortages and transportation shutdowns Sandy inflicted on the Northeast United States were on a massive scale — as was the loss of life, which totaled more than 100 dead, many in flood-prone sections of New York City.

Sandy generated insured losses of as much as $20 billion, according to early estimates, and total economic damages of up to $50 billion. The high end of those estimates would make Sandy, in real terms, the third-costliest storm in U.S. history, after hurricanes Katrina in 2005 and Andrew in 1992.

Yet although the storm hit the nation’s most densely populated region, strong advance planning by local, s