The historic cyclone that made landfall on this date last year was so powerful and devastating that it was designated a "superstorm," had its name retired, and entered the tropical storm hall of fame.
But hurricane experts fear that something far worse than Sandy, blamed for $50 billion in damage, is brewing. In the next two decades, the nation could experience a $500 billion storm.
The sea level is rising, and global warming might affect future storms. But even if the world's temperature stops rising before you finish this paragraph, hurricanes far more damaging than Sandy are all but a certainty, they say.
Despite unprecedented forecasting, monitoring, and warning abilities, and a record period of hurricanes avoiding landfall, the disaster remains one of the nation's most robust growth industries, with almost unlimited potential.
"Quite simply, there are more people and more infrastructure in harm's way," said Margaret Davidson, the National Oceanic and Atmospheric Administration's acting director of coastal resource management.
Jersey Shore real estate alone is worth about $95 billion -- an 11-fold increase since 1962 -- and industry officials estimate that properties in hurricane-vulnerable areas have an insured value of $10 trillion.
Disaster costs have exploded in the last 25 years.
No U.S. hurricane caused more than $1 billion in damage before Hugo in 1989. From 2005 through fiscal 2011, the Federal Emergency Management Agency has spent more than $50 billion on tropical storms -- 90 percent of all disaster money -- even though no major hurricanes made a U.S. landfall after 2005.
Sandy stimulated discussions about mitigation, emergency preparedness, communication, and even sand dunes. But given the nation's hurricane history, Davidson said, she wondered about any lasting impact.
"How many lessons have we actually learned well?" she said. "I'd like to see us make some new mistakes, frankly, as opposed to repeating the same old mistakes at greater expense."
Sandy's fundamental lesson, said Roger Pielke Jr., disaster specialist at the University of Colorado, is: "Planet Earth is a dangerous place, where extreme events are commonplace and disasters are to be expected."
Pielke has devised methods to analyze hurricanes in the period of record and estimated what those storms would cost if they struck today, given population, building, and inflation -- what he calls "normalized" damage.
Far and away No. 1 on the list is the Great Miami Hurricane of 1926 at $183.3 billion. The estimates grow about 5 percent annually. Thus a similar storm hitting the same area 20 years from now would yield close to $500 billion in damage.
Katrina, the 2005 hurricane blamed for thousands of deaths and leaving FEMA's National Flood Insurance Program swamped in a red tide of debt, is No. 4, at $80 billion. Sandy is No. 7.
One factor that argues for more expensive future storms is the rising sea level. Seas generally have been rising for thousands of years as the planet has warmed, and in recent years the rising has accelerated, the result of melting ice and the greater volume of warm water.
Sandy is a powerful illustration of the importance of water levels. It made landfall during one of the highest tides of the year along the New Jersey and New York coasts.
Had it arrived at low tide, said Adam H. Sobel, an atmospheric scientist at Columbia University, the water level in New York Harbor would have been around 9 feet -- about the level of Irene in 2011, not a big deal in terms of storm surge -- rather than 14 feet.
"Manhattan wouldn't have lost power," he said. "The subways wouldn't have flooded."
Higher seas mean more damaging storm surges and also subtle increases in wave power.
"We know sea level is already rising," said Ben Strauss, a climate scientist at Climate Central, an independent research organization. "Every coastal flood is starting from a higher launch pad.
"Even if there were no increase in storm intensity, we would still see much worse flooding in the future."
It is unclear whether global warming is affecting hurricane intensity, according to the 10 scientists who authored a 2010 paper, but they said the models suggest an increase in intensity of 2 percent to 11 percent by the end of the century.
"I have not seen anything that would suggest any change in storm strength," said Frank Marks, director of NOAA's Hurricane Research Division. "Given that the warming is expected to affect the polar regions more than the tropics, I doubt we will see much change in the tropical cyclones due to warming for some time."
The last eight tropical-storm seasons have been unprecedented in terms of the lack of hurricane landfalls. No major hurricane -- one with winds of at least 111 mph -- has hit the U.S. coast since 2005, and no hurricane of any strength has made a Florida landfall since then. Both are record streaks. This season, for the first time since 1982, no major hurricane has formed in the Atlantic Basin, not even a fish storm.
No scientist has attributed the gentleness to global warming, however, and no one expects that luck to continue.
Some season soon, experts say, something worse than Sandy is all but inevitable, even without changes in storm intensity. The pins are set up, and the weight of the ball isn't going to make much difference.
"We really can ill afford to keep having these $30 (billion) to 100 billion disasters," NOAA's Davidson said.
"Now, we think we're going to see $100 billion disasters on a regular basis."
(c) 2013 McClatchy News Service