A spokeswoman for Experian, which runs a Carfax competitor called AutoCheck, said the area that got blasted by Sandy has 9 million registered cars, far more than in the Gulf region struck by Katrina.
On Wednesday, the National Automobile Dealers Association put out a statement estimating that 200,000 or more flooded cars could be resold as used.
The trade organization warned that the storm could crimp the supply of clean used cars, potentially driving up prices. But its estimate was based on reports from third parties that showed 600,000 cars were damaged in Katrina and that Sandy would cause about one-third of the dollar damage from Katrina.
"There was not an incredible amount of science behind it," conceded Jonathan Banks, executive automotive analyst with the NADA Used Car Guide.
Katrina overwhelmed low-lying areas of the Gulf Coast, including New Orleans, which is below sea level, causing widespread flooding. Many people in Katrina's path didn't evacuate, and car dealers didn't have many options to protect inventories.
In hard-hit New Jersey, flooding from Sandy was mainly confined to a strip along the coast from Atlantic City to New York, and most people evacuated those areas, Appleton said.
In the western part of the state, "unless a tree fell on your car, your car wasn't even at risk," he said.
Chris Basso, another Carfax spokesman, said the company relied on an estimate from a trusted industry source in putting out its news release. He said it was just an estimate, and the final number won't be known for a while.
"All we're trying to do is make sure people are looking out for these cars," he said. "Because eventually they're going to make their way back onto the road."
Regardless of the predictions, thousands of flood-damaged cars will certainly be resold, and buyers need to be cautious.