The whims of nature kept Hurricane Gustav from living up to its advance billing as the "mother of all storms." But state and federal officials also wisely avoided the carnival of mistakes made when Hurricane Katrina struck three years ago.

Mandatory-evacuation orders quickly turned The Big Easy into The Big Empty. Emergency transportation was readily available. The National Guard was poised for action. The Federal Emergency Management Agency and city and state officials worked in close coordination.

Government and social service agencies in Texas and other states also prepared for evacuees. Thousands of people weren't left huddled helplessly in the Louisiana Superdome or stranded in homes and hospitals or on freeway overpasses. People were safely in shelters far from New Orleans well before Gustav arrived.

Luck also played a role in sparing New Orleans. Gustav didn't strike full force at the city's most vulnerable points and probably would have been more ferocious had it not swept over Cuba en route to the Gulf Coast.

That's fortunate for New Orleans. Only about 25 percent of the city's levee system has been improved since 2005 to withstand a 100-year storm, let alone a hurricane the magnitude of Katrina. That storm, according to the U.S. Army Corps of Engineers, was a 1-in-396-year occurrence.

New Orleans residents must take the threat of the next hurricane – and there will be others – as seriously as they did this one. Levee improvements must be completed and complacency must not creep back into the city's collective mindset.

In poker terms, New Orleans drew to a weak inside straight and won when it got the longshot card it needed. But it is a foolish bet, and next time it could be a loser.