By the time Hurricane Charley hit Punta Gorda, Fla., on Aug. 13, the forecasters at Jersey City (N.J.)-based Insurance Services Office Inc. already had a rough idea of what it would cost the property and casualty industry.

Scientists at its AIR Worldwide subsidiary in Boston used computer modeling techniques to put the initial estimate at $6 billion to $10 billion.

A few weeks later, the losses from Frances – which was less intense than Charley but lasted longer and spread over a wider swath – were estimated at $5 billion to $10 billion.

And as Ivan was bearing down on Mobile, Ala., on Wednesday, prognosticators were hard at work trying to get a handle on the hit insurers would take.

“People have been working every weekend for the past month and staying late into the night. It’s somewhat exhausting,” said Michael Gannon, spokesman for AIR.

But estimating losses from hurricanes and other disasters represents only a small part of what Insurance Services does, said Frank Coyne, chairman and chief executive of the company, known as ISO.

It is also one of the insurance industry’s top number-crunchers, claiming ownership of the world’s largest database of insurance premium and loss data (9.3 billion records), stored in its mainframe computers on the Hudson River waterfront.

Insurers use the data and ISO’s analyses to figure out whether to write policies in certain areas and how much to charge. More than 90 percent of the nation’s insurers pay to use an ISO database to help detect fraud.

The company has detailed data on many large commercial properties, monitoring such things as the quality of sprinkler systems and the layout of fire escapes to help insurers assess their risk at their desktop computers.

ISO also assesses municipalities on their building codes and fire department response times.

Read your auto or home policy, and chances are there is an ISO copyright on the bottom, as ISO is also a leading writer and producer of boiler plate insurance forms. If the federal government decides after 2005 to stop funding its terrorism backstop insurance program, ISO has new policy forms approved for use in most states, including New Jersey, ready to go. The forms would be used by companies that offer policies excluding or limiting coverage for terrorism-related losses.

The company’s Property Claim Services division follows up on AIR’s high-tech prognostics by sending field representatives into the disaster areas and by conducting surveys of the insurance companies that send in claims adjusters.

The unit issued a preliminary estimate on Aug. 24 of the losses expected from Charley: $6.76 billion. A preliminary estimate on Frances is expected soon.

The bulk of the claims from Charley, an estimated 440,000, are homeowner policies. The average amount per homeowner claim is $8,534 for a total of $3.76 billion, including $100 million in claims for damage to boats.

Losses from claims from businesses were estimated at $2.7 billion. Claims against auto polices were estimated at $300 million.

“Florida really took it on the chin,” said Gary Kerny, assistant vice president of the PCS unit.